Millie Bobby Brown and Noah Schnapp's Friendship Timeline

Millie Bobby Brown best friend challenge!
Millie Bobby Brown best friend challenge!

Noah Schnapp/Youtube

From strangers to Stranger Things.

Millie Bobby Brown and Noah Schnapp are more than just costars on the hit Netflix series, they're real-life friends as well — a bond they've built ever since they started shooting the show's debut season in 2015.

Although Brown's Eleven and Schnapp's Will Byers didn't have much onscreen interaction within the first three seasons, the two have grown extremely close behind the scenes.

Whether they're tearing up red carpets, filming TikTok challenges, or hitting the dance floor at award show afterparties, Brown and Schnapp always bring the fun.

They've also grown up alongside each other! When Brown first auditioned for Stranger Things, she was 11 years old. Meanwhile, Schnapp was 9 years old at the time. Now, as the show enters its penultimate fourth season, Brown is 18 and Schnapp is 17.

Between their silly videos and sweet photos together, take a look back at Brown and Schnapp's friendship through the years.

RELATED: David Harbour Says Stranger Things' Endgame — Including Hopper's Fate — Is 'Quite Moving'

Dec. 16, 2015: Millie Bobby Brown and Noah Schnapp's first day on the Stranger Things set

Stranger Things cast
Stranger Things cast

Noah Schnapp/Instagram

While Stranger Things season one began filming in September 2015, Schnapp documented his first day on set with an Instagram photo posted on Dec. 16.

Brown excitedly posed next to Schnapp, while the rest of the gang — Caleb McLaughlin, Gaten Matarazzo, and Finn Wolfhard — also gathered around for the selfie.

"Day one here we go," Schnapp captioned the post.

July 11, 2016: Millie Bobby Brown and Noah Schnapp's first red carpet together

Millie Bobby Brown and Noah Schnapp
Millie Bobby Brown and Noah Schnapp

Amanda Edwards/WireImage

Marking the first of many, Brown and Schnapp hit the red carpet together at the Stranger Things season 1 premiere on July 11, 2016. They posed alongside cast members Winona Ryder, McLaughlin, Matarazzo, and Matthew Modine.

Jan. 7, 2017: Millie Bobby Brown and Noah Schnapp at the BAFTA Tea Party

Millie Bobby Brown and Noah Schnapp Friendship Timeline
Millie Bobby Brown and Noah Schnapp Friendship Timeline

Noah Schnapp Instagram

Ahead of the award show circuit, in which the Stranger Things cast famously made their rounds, Brown and Schnapp attended the annual BAFTA Tea Party event in Beverly Hills on Jan. 7, 2017.

The dynamic duo were newbies on the star-studded scene at the time but made sure to snag a selfie with Justin Timberlake while they were there.

Jan. 8, 2017: Millie Bobby Brown and Noah Schnapp at the Golden Globes afterparty

Millie Bobby Brown and Noah Schnapp
Millie Bobby Brown and Noah Schnapp

Jason LaVeris/FilmMagic

The dynamic duo didn't just walk the red carpet at the 2017 Weinstein Company and Netflix Golden Globes afterparty on Jan. 8, they struck some fierce poses as well! Brown hit a power stance with her hands on her hips, while Schnapp crouched down and pointed at the camera.

Jan. 29, 2017: Millie Bobby Brown and Noah Schnapp in the SAG Awards trophy room

Millie Bobby Brown (L) and Noah Schnapp hug backstage after winning the award for the Outstanding Ensemble in a Drama Series award for 'Stranger Things'
Millie Bobby Brown (L) and Noah Schnapp hug backstage after winning the award for the Outstanding Ensemble in a Drama Series award for 'Stranger Things'

Matt Winkelmeyer/Getty Images

Emotions ran high for the Stranger Things cast when they won the award for outstanding ensemble in a drama series at the 23rd Annual Screen Actors Guild Awards on Jan. 29, 2017.

After a powerful and politically-charged speech delivered by David Harbour, who plays Jim Hopper on the series, Brown and Schnapp embraced each other backstage in celebration.

Jan. 19, 2017: Millie Bobby Brown and Noah Schnapp at the SAG Awards afterparty

Millie Bobby Brown (L) and Noah Schnapp attend The Weinstein Company & Netflix's 2017 SAG After Party
Millie Bobby Brown (L) and Noah Schnapp attend The Weinstein Company & Netflix's 2017 SAG After Party

Phillip Faraone/Getty Images for The Weinstein Company/Netflix

Following a successful SAG ceremony in 2017, the Stranger Things cast let loose at the afterparty later that evening. Brown and Schnapp enjoyed themselves as they posed together for a silly photo holding up fistfuls of french fries.

RELATED: Millie Bobby Brown's Hollywood Evolution in Pictures

June 6, 2017: Millie Bobby Brown and Noah Schnapp hug on the red carpet

Millie Bobby Brown and Noah Schnapp
Millie Bobby Brown and Noah Schnapp

Jason LaVeris/WireImage

Brown and Schnapp sweetly wrapped their arms around each other on the red carpet at the Stranger Things FYC event at Netflix FYSee Space in Beverly Hills on June 6, 2017.

May 19, 2018: Millie Bobby Brown and Noah Schnapp hold hands on the red carpet

Millie Bobby Brown and Noah Schnapp
Millie Bobby Brown and Noah Schnapp

Rodin Eckenroth/Getty

A year later, Brown and Schnapp arrived at the same event in a similar fashion, this time walking the Netflix FYSee red carpet hand-in-hand.

July 17, 2018: Millie Bobby Brown and Noah Schnapp dance to Drake

Sometimes filming can take the Stranger Things cast and crew well into the evening, but the cast has fun while doing it. Schnapp shared a fun video of himself alongside Brown doing the iconic choreographed dance to Drake's hit "In My Feelings," captioning the clip, "night shoots" on July 17, 2018.

Sept. 17, 2018: Millie Bobby Brown and Noah Schnapp at the Emmy Awards afterparty

Noah Schnapp and Millie Bobby Brown attend the 70th Emmy Awards Governors Ball
Noah Schnapp and Millie Bobby Brown attend the 70th Emmy Awards Governors Ball

Alberto E. Rodriguez/Getty Images

The Stranger Things cast loves to have a good time, especially when it comes to award show afterparties. Coming off a big night at the 70th Annual Emmy Awards, Brown and Schnapp were all smiles when they held each other close for a photo on Sept. 17, 2018.

Oct. 31, 2018: Noah Schnapp dresses as Millie Bobby Brown's Stranger Things character for Halloween

milli-bobby-brown
milli-bobby-brown

Millie Bobby Brown/Instagram

There's no denying that Brown's character Eleven has been a popular Halloween costume over the years, so much so that even Schnapp transformed into the nose-bleeding, telepathic character!

Brown shared a photo on Instagram posing beside Matarazzo, Wolfhard, McLaughlin, Schnapp, and Sadie Sink on the spooky holiday in 2018.

June 28, 2019: Millie Bobby Brown and Noah Schnapp at the Stranger Things season 3 premiere

Millie Bobbie Brown and US actor Noah Schnapp attend Netflix's "Stranger Things 3" premiere
Millie Bobbie Brown and US actor Noah Schnapp attend Netflix's "Stranger Things 3" premiere

CHRIS DELMAS/AFP via Getty Images

Schnapp appeared to be fixing the tulle train on Brown's gown as the two playfully posed for a picture at the Stranger Things season 3 world premiere on June 28, 2019.

RELATED: Bridgerton's Nicola Coughlan Auditioned for Maya Hawke's Stranger Things Role: 'She Was Far Better'

Aug. 15, 2019: Millie Bobby Brown and Noah Schnapp test their friendship

Millie Bobby Brown best friend challenge!
Millie Bobby Brown best friend challenge!

Noah Schnapp/Youtube

While Brown and Schnapp have publicly deemed themselves each other's "best friend" in the past — such as in their interview with Wired — the two put their true friendship to the test in a video uploaded to Schnapp's YouTube channel in 2019.

Brown and Schnapp filmed themselves answering a number of questions while keeping a tally to see "who knows each other best."

Jan. 19, 2020: Millie Bobby Brown and Noah Schnapp talk about their "proudest prank"

In addition to throwing random dance parties and filming social media challenges, Brown and Schnapp are always pulling pranks on set as well. The two teamed up on a Stranger Things crew member who was about to get married to pull off their "proudest prank" yet, Schnapp told PEOPLE on the 2020 SAG Awards red carpet.

"We told one of our crew members her wedding was cancelled and she started crying," Schnapp said. "That was a pretty good one. It's our proudest prank. I was like her manager and we called them on the phone and we were right next to her like looking at her and she was bawling, and it was kind of bad but we told her after and she was okay."

October 2021: Millie Bobby Brown pranks Noah Schnapp

While Schnapp is regarded as the prankster of the Stranger Things cast, Brown managed to pull a fast one on him while filming the show's fourth season.

"On our last day of filming season 4, Millie, she got the whole crew together and she bought like, 2000 water balloons," Schnapp told PEOPLE. "She called me back to our base camp to give her a hug goodbye. I got there and I was like, 'Where is she at? Let me go say goodbye.'"

Schnapp soon realized Brown had something entirely different planned: "Her and 30 other crew members came out behind the trailers with each, like, 100 water balloons, just chucking them at me!"

Feb. 19, 2022: Noah Schnapp wishes Millie Bobby Brown a happy 18th birthday

Millie Bobby Brown and Noah Schnapp Friendship Timeline
Millie Bobby Brown and Noah Schnapp Friendship Timeline

Noah Schnapp Instagram

Schnapp shouted out Brown in honor of her 18th birthday with a sweet Instagram tribute on Feb. 19, 2022. The post pictured Brown playfully grabbing Schnapps cheeks as the two wrapped their arms around each other.

"Happy 18 to this crazy girl…thanks @strangerthingstv for bringing this crazy duo together🤞🏼" Schnapp captioned the photo.

Schnapp posted another roundup of images from Brown's big birthday bash. Among the series of photos, one included Schnapp behind the mic while Brown looked emotional as he spoke. The roundup concluded with the besties battling it out on the dance floor in typical Brown-Schnapp fashion.

March 12, 2022: Noah Schnapp talks about Millie Bobby Brown on The Tonight Show Starring Jimmy Fallon

Schnapp made his Tonight Show return as he talked about all things Stranger Things on March 12, 2022. While he was there to promote the show's fourth season, he shared how emotional things got for him, Brown, and the rest of the cast when it registered that the show's fifth and final season is right around the corner.

He explained that after the Stranger Things creators shared a letter about how it was "the beginning of the end" of the show, Schnapp "started balling." He added, "I texted Millie ... who was like, 'You're crying too? So am I!'"

RELATED: See Stranger Things' Noah Schnapp and His Family Jump for Joy in His College Acceptance Video

May 2022: Millie Bobby Brown and Noah Schnapp compete in a Fruit by the Foot race

Millie Bobby Brown and Noah Schnapp Friendship Timeline
Millie Bobby Brown and Noah Schnapp Friendship Timeline

Millie Bobby brown/Youtube

Another challenge Brown and Schnapp hilariously took part in on set was a Fruit by the Foot race, where they raced to eat an entire roll of the treat.

Brown uploaded the race to her TikTok and chatted about it when she appeared on The Tonight Show. After beating Schnapp in their competition, she then challenged Jimmy Fallon to the sugary showdown.

May 18, 2022: Noah Schnapp compliments Millie Bobby Brown's acting skills in Stranger Things season 4

Millie Bobby Brown as Eleven and Noah Schnapp as Will Byers in "Stranger Things" Season 4
Millie Bobby Brown as Eleven and Noah Schnapp as Will Byers in "Stranger Things" Season 4

Courtesy of Netflix

Despite being best friends in real life, Brown's Eleven and Schnapp's Will haven't interacted much on the show — but come season four, that dynamic changes.

"To get to work with Millie, it's been such a blast," Schnapp told Extra of working with his best friend. "She's so talented and just working off of her is amazing and I just learn so much with her, so great ride."

Schnapp discussed the best part about working alongside Brown on the Netflix show's fourth installment during a roundtable attended by CBR.

"I love their sibling relationship that we get to show this season," Schnapp said. "You kind of see Will as an over-protective brother to El this season, through all her struggles in high school."

He added: "It's been fun, off set just to be together and be able to play that because prior to that, we never really had any scenes or much [chance] to work together. That was the first time we really got to be together and work alongside each other, and it was great."

May 2022: Noah Schnapp and Millie Bobby Brown get emotional talking about Stranger Things ending

Brown opened up to Variety about how she and her castmates aren't quite ready for Stranger Things to wrap. "We're in that denial phase right now where we're not choosing to accept it. We're the ones that you can't really talk about it around," she said of herself and Schnapp.

Noah added that they were especially emotional on the last day of shooting season 4. "I remember, I was going up to Millie, and I was like, 'Are you crying? Are you gonna cry? Are you crying or upset?' And she's like, 'No, no, we're not talking about it yet. There's still seven more hours. It's not over yet.'"

However as soon as they wrapped, Brown added that they began sobbing like "cartoons with tears coming out of their eyes." "So we are choosing not to speak of it," she added.

May 14, 2022: Millie Bobby Brown and Noah Schnapp attend the Stranger Things season 4 premiere

US actor Noah Schnapp (L) and British actress Millie Bobby Brown attend "Stranger Things" season 4 premiere at Netflix Brooklyn in New York City on May 14, 2022.
US actor Noah Schnapp (L) and British actress Millie Bobby Brown attend "Stranger Things" season 4 premiere at Netflix Brooklyn in New York City on May 14, 2022.

ANGELA WEISS/AFP via Getty

Brown and Schnapp stepped out in style when they hit the red carpet at the Stranger Things season 4 premiere in New York City. The carpet was a nostalgic one for the cast, as this penultimate season marks three years since season 3 was released. (And the kids are all grown up!)

Brown oozed glamour in a Louis Vuitton belted white, floor-length dress. Meanwhile, Schnapp wore a pink jacket with popped lapels over an all-white ensemble.

May 27, 2022: Millie Bobby Brown and Noah Schnapp post behind-the-scenes content

In celebration of the Stranger Things season 4 release, Brown and Schnapp both shared some never-before-seen content from set on their respective Instagram accounts.

"ST4 is out now… Thanks to the best cast and crew for pouring their lives into this show and creating a masterpiece❤️" wrote Schnapp alongside a carousel of candid pictures and videos taken during production.

Brown captioned her post: "so many giggles! so much hard work! we hope you like it 💗 @strangerthingstv." Her carousel included several pics with the cast, in addition to a silly solo snap with Schnapp that kicked off the roundup.

June 2, 2022: Millie Bobby Brown and Noah Schnapp reveal their marriage pact

Brown and Schnapp admitted during an interview with MTV News that they formed a pact to tie the knot if they're both single by the time they're 40.

"We said if we're not married by 40, we'll get married together," revealed Brown. "Because we'd be good roomies." Schnapp added, "We would."

Brown made sure to clarify the pair would be wed "completely platonically." She then added, "No kids, though, cause I could not deal with a child of yours."

June 2, 2022: Noah Schnapp makes a guest appearance during Millie Bobby Brown's Hot Ones interview

Schnapp was by Brown's side when he made a surprise appearance during her Hot Ones interview, hosted by First We Feast's Sean Evans. The actor stepped into the scene to kick things off with wing number one, a "mild" introduction to the ten-wing challenge that got increasingly spicier down the line.

The two sat beside each other, clinked wings for a "cheers," and joked with each other while enjoying the first. Schanpp poked fun at Brown when he commented on her self-proclaimed high tolerance with hot food, in which he touted, "I'm much better at spice."

Brown hilariously quipped, "Well, they didn't invite you on the show!"

June 22, 2022: Millie Bobby Brown and Noah Schnapp share a laugh

Brown and Schnapp find fun in nearly everything they do, even when work is involved. The dynamic duo couldn't contain their laughter when attempting to shoot a promo for Stranger Things 4, Volume 2.

Schnapp shared a behind-the-scenes clip of the silliness to TikTok, writing, "Millie and I are clearly experts in press," as they struggled to get the words out of their mouths.

November 10, 2022: Millie Bobby Brown lies about Noah Schnapp's bowl cut

Brown answered questions about Stranger Things while taking Vanity Fair's lie detector test. At one point, she was asked about Schnapp's iconic bowl cut from the series. "Would a best friend let someone have this haircut?" the interviewer asked, sliding a photo of Schnapp to her.

"He put himself in that position," Brown replied.

When asked if she thinks he looks good, Brown nervously said, "I do think he looks great."

However, it's clear the actress had an issue with the '80s hairstyle as the polygraph examiner immediately announced, "That's a lie."