Macaulay Culkin's birthday message to Brenda Song includes a funny request

Macaulay Culkin is sending a heartfelt 36th birthday tribute to his fiancée, Brenda Song.

The "Home Alone" star posted a photo of the former "Suite Life of Zack & Cody" star wearing a robe with a towel wrapped around her hair March 27 on Instagram.

"Happy birthday to the best friend, mother, ally, colleague, lover, and partner I could ever wish for. You are my reason. I love you," he wrote in his caption.

He added, "P. S. The milk is due. Can you pick some up on your way home from work?" along with a photo of a carton of milk.

Culkin's sweet shoutout to his bride-to-be comes less than four months after Song showed up to cheer the actor when he received his star on the Hollywood Walk of Fame on Dec. 1.

The two former child stars began dating in 2017 while filming Seth Green's comedy-drama "Changeland" in Thailand.

"I have a good life now. I've got a special lady friend. We have a dog and a cat. It's one thing to exchange keys. It's another to get a cat," Culkin, 43, joked of the seriousness of the pair's relationship during a 2018 appearance on "The Joe Rogan Experience" podcast.

In April 2021, Culkin and Song welcomed their first child, a son named Dakota. The couple became parents again more than a year ago when their second son was born.

Read on to learn more about the love story between Culkin and Song.

2013: Culkin and Song meet on the set of the sitcom 'Dads'

When Song appeared on Culkin's "Bunny Ears" podcast in April 2018, the couple revealed that they initially met in 2013 when Culkin visited the set of Song's short-lived sitcom "Dads," which starred Seth Green and Giovanni Ribisi.

“Yeah, she totally brushed me off, completely,” Culkin recalled to the podcast's guest Matt Bennett.

“I was focused,” Song corrected.

Culkin continued insisting that Song didn't like him at first, prompting Bennett to ask Song what it was about Culkin that turned her off.

"It was the man bun," she joked.

2017: Culkin and Song begin dating while filming 'Changeland'

Romance blossomed between Culkin and Song in 2017 while filming Seth Green's 2019 comedy-drama "Changeland."

Culkin, who previously dated Mila Kunis for eight years and had split from wife Rachel Miner, and Song, who ended an engagement to Trace Cyrus in 2012, were spotted grabbing dinner at Craig’s in West Hollywood in July 2017, according to People.

August 2017: Song shares a group pic featuring Culkin on Instagram

Culkin made his first appearance on Song's Instagram page in August 2017. The "Party Monster" star sported bunny ears when he appeared alongside Song and Seth Green in a festive group shot.

April 2018: Culkin reveals he wants to have kids with Song

During the "My Girl" star's 2018 appearance on “The Joe Rogan Experience" podcast, he revealed that he wanted to have children with Song.

"I'm going to make some babies," joked Culkin. "This one's a good one. I'm probably going to put some babies in her. ... We've definitely been practicing."

September 2018: Song gushes that 'everything's wonderful' with Culkin

In September 2018, Song spoke briefly to Us Weekly about her romance with Culkin when the couple attended a Stand Up To Cancer fundraiser in Santa Monica.

“It’s great!” gushed the "Social Network" star. “I don’t like to talk about my personal life, but everything’s wonderful and I’m happy.”

June 2019: The couple attend the 'Changeland' premiere together

In July 2019, Culkin and Song attended the Los Angeles premiere of their movie "Changeland" together.

"Two years ago almost to the day, I went to Thailand and made @changelandmovie with my best friends. It’s out today in theaters and VOD!! Please check it out!" Song captioned an Instagram pic of the movie's stars and writer-director Seth Green.

August 2019: Song celebrates her 'favorite human' on his 39th birthday

The former Disney Channel star honored Culkin, calling him her "favorite human" when he turned 39 on Aug. 26, 2019.

"Happy birthday to my most favorite human @culkamania. Thank you for all that you do. I love you the mostest," Song wrote on Instagram alongside a photo of balloons spelling out the words "Happy B-day Mack."

November 2019: Culkin guest stars on Song's TV show 'Dollface'

Culkin made a guest appearance on his girlfriend's Hulu series "Dollface" in November 2019.

Culkin played Dan, a love interest for Shay Mitchell's character, Stella, who Song's character, Madison, suspects is a serial killer.

February 2020: Culkin reveals that he and Song are trying for a baby

Culkin opened up about how he and Song were trying to start a family for a February 2020 cover story interview with Esquire.

“We’re figuring it out, making the timing work. Because nothing turns you on more than when your lady comes into the room and says, ‘Honey, I’m ovulating,'" Culkin joked to the publication.

The actor gushed about his life with Song, saying, "I mean, look at me: I got money, I got fame, I got a beautiful girlfriend and a beautiful house and beautiful animals.

"It took me a long time to get to that place, and I had to have that conversation with myself and go, like, Honestly, Mack? It’s not so bad. I want for nothing and need for even less. I’m good, man.”

February 2020: Song describes Culkin as 'incredibly kind'

Song also talked to Esquire for the story about Culkin, gushing that her partner's kindness and authenticity make him "sexy" in her eyes.

“People don’t realize how incredibly kind and loyal and sweet and smart he is,” Song said. “Truly what makes Mack so special is that he is so unapologetically Mack.”

She added, “He knows who he is, and he’s 100% OK with that. And that to me is an incredibly sexy quality.”

August 2020: Song honors Culkin on his 40th birthday

Song sang Culkin's praises in a heartfelt tribute on the actor's 40th birthday in August 2020.

"Happy 40th birthday to this magical being," she captioned an Instagram pic, taken from behind, that showed both actors modeling matching flannel pajamas with their names written on the back.

"I could sit here and write endlessly about how wonderful, kind, loving, genuine, loyal, honest, brilliant and hilarious you are, and how grateful I am that I get to share and do this life thing with you. But firstly, that would take me an eternity and secondly, you won’t even see this because you don’t ever use instagram. Hahaha," she continued.

"My unicorn that I never thought could exist, I am luckiest person in the world because I am loved by you," she concluded.

April 2021: The couple welcome their first child, a son

Culkin and Song became parents for the first time in April 2021 when they welcomed a son they named Dakota in honor of Culkin's late sister, who died in 2008 after being hit by a car.

November 2021: Song shares a cute photo with Culkin

In November 2021, Song shared a photo of her and Culkin hamming it up with a Los Angeles Rams mascot on Instagram, writing, "Very few things can get us out of the house and away from our son."

January 2022: The couple's engagement is first reported

Culkin and Song's engagement was reported by E! News in January 2022, shortly after Song began wearing what looked to be an engagement ring in public.

January 2022: Song opened up about parenting with Culkin

While speaking with The Cut in January 2022, Song opened up about how she and Culkin juggle parenting duties for then 9-month-old Dakota.

"My boyfriend and I are very hands-on. We don’t have a nanny, but my mom has been here with us since my son was born," she said.

"I think when you and your partner have kids, especially the first few months, you don’t have the patience to be polite with each other," she continued. "Being communicative when you need help is so important. Instead of having set duties, we just feel each other out. I’ll be putting my son down and my partner is like, “Let me feed the animals and get dinner ready.”

Song also described how the first-time parents made sure to carve out time for one another each night.

“My boyfriend and I always get into bed and chat about our days and the next day,” said Song. “When I was working he’d wake up with me to chat. Now we do it at night, after our son goes down. It calms me. It sounds small, but I cherish it. It’s nice to wind down with someone you love.”

April 2022: The couple celebrated Dakota's 1st birthday

The new parents celebrated their son Dakota's first birthday at Sesame Place San Diego, with Culkin sharing a photo on Instagram that showed him and Song interacting with an employee dressed as Elmo.

"Just want to send out a BIG thank you to the amazing people over at Sesame Place in San Diego for hosting my son’s first birthday,” Culkin captioned the pic. “They made a little boy’s dreams come true. And my son also had a great time.”

Song posted the same image, joking, "Thank you sooo much to all the amazing people at Sesame Place San Diego for making BOTH my boys’ dreams come true and for hosting the most magical first birthday for our son! We had so much fun!"

September 2022: Song opens up about wedding planning with Culkin

Song talked to People about planning her wedding to Culkin while juggling motherhood.

“Wedding planning is so expensive and it takes up so much time,” she told the publication. “Being a new mom, we’re so busy."

December 2022: The couple welcome baby No. 2

Culkin and Song welcomed their second child, a son named Carson, in December 2022 but kept the news under wraps, Us Weekly reported months later.

The same month, Culkin's younger brother, former "Succession" star Kieran Culkin, confirmed to People that the couple had become parents again.

“(They) live in Los Angeles and we live in New York. I have a 1-year-old and a 3-year-old, and as busy as I am, there’s just no getting on a plane and going, and same with them,” he said. “I haven’t met No. 2 yet. We just haven’t been able to figure that out.”

January 2024: Song congratulates Kieran Culkin on his Emmy win

Song cheered on her future brother-in-law Kieran Culkin following the actor’s Emmy win at the 75th Emmy Awards on Jan. 15.

“YAY KIERAN!!!!!!!” Song wrote next to a photo of Kieran Culkin that she shared in her Instagram stories. He took home the award for lead actor in a drama series for his performance as Roman Roy in the HBO drama “Succession.”

March 27, 2024: Culkin honors Song on her 36th birthday

On March 27, Macaulay Culkin toasted his bride-to-be in honor of her 36th birthday. Next to a pic showing Song in a robe with a towel wrapped around her hair that he posted on Instagram, the actor wrote, “Happy birthday to the best friend, mother, ally, colleague, lover, and partner I could ever wish for. You are my reason. I love you."

He added a second pic of a carton of milk, joking, “P. S. The milk is due. Can you pick some up on your way home from work?”

This article was originally published on TODAY.com