Whether or not you're familiar with Jack Antonoff by name, you're guaranteed to have had his music stuck in your head over the last seven years.
As the main member of Bleachers, he's releasing his band's second album Gone Now on June 2. As a reluctant celeb, he's known for being BFFs with Taylor Swift and for his long-term relationship with Girls star Lena Dunham. As a son and brother, he's known for "forgetting his wallet" when it comes to paying for bagels.
And as a songwriter? Well, he's everywhere. From his prior bands (inlcuding the Grammy-winning Fun.) to the songs he's co-written/produced for others, Jack has helped create some of the most prominent pop songs of the 2010s. For him, it's his music hobby to take a break from his music job.
"I need a hobby, and I don't want it to be basketball. I want it to be music," he told Vulture in 2014. "So to get away from music, I do other music. If I'm producing someone's song or writing with someone else, then doing a Bleachers song or a fun. song is an escape and it keeps me creative and it keeps me locked into what I want to do. If something's making me crazy, I need to go somewhere else and I don't want that thing to be yoga."
Check out some of Jack's most famous hobby work below:
1. "I Don't Wanna Live Forever," Zayn & Taylor Swift 
The only way to avoid having this earworm stuck in your head is to keep your radio off at all times. Jack teamed up with Taylor to co-write this track for the Fifty Shades Darker soundtrack. This isn't their first time writing together, but more on that later.
2. "Green Light," Lorde 
You may remember seeing Jack with an upright piano in both the music video for "Green Light" and Lorde's SNL performance of "Liability." The pair has worked together on writing and production for her upcoming album Melodrama, and still has enough time left over to constantly hype each other on Twitter.
3. "We Are Young," fun. featuring Janelle Monáe 
Who doesn't love fun.? Jack co-wrote on each of their albums, and their biggest hit was the Hot 100-topping "We Are Young," named Song of the Year at the 2013 Grammys. Beyond that, it's been the inspiration for covers of all kinds: it was picked up for Glee before it was even released, a Spanish version was used in a Taco Bell Super Bowl commercial, and it was recorded in Similish for a Sims expansion pack -- because sometimes the internet gives us things we didn't realize we needed.
And as a member and core songwriter of this currently-inactive trio, Antonoff of course played a large part in crafting their two other Top 40 hits, "Some Nights" and "Carry On."
4. "Dope," Fifth Harmony 
If you didn't pick up the deluxe version of Fifth Harmony's latest record, you may have missed this one. Jack co-wrote and produced this track, but took it a step further by recording all of the instruments himself as well. That's "pretty f--king dope, just so you know."
5. "Brave," Sara Bareilles 
If a Microsoft commercial airs and "Brave" isn't played in the background, did it really happen? Ever since Jack helped write this song, we're fairly certain execs have decided its utmost necessity, whether soundtracking tech or inspirational, coming-of-age crescendos. The Grammy-nominated song took on a life of its own after its release; the University of Minnesota Masonic Children's Hospital posted a heart-wrenching cover video, inspiring Sara to start the Brave Enough postcard initiative.
6. "Firecracker," Steel Train 
Steel Train was Jack's first band. He used to meticulously keep track of every show they ever played, where it was, when in the set they performed, and how much they were paid. According to him, the sheet said "$0" more often than not. But he can tell you the exact information of his first ever paid gig, and the music sounds like the younger brother of Bleachers' album (which, y'know, makes sense). Here's a handpicked favorite from Steel Train's second full length, Trampoline. Jack had a knack for writing great choruses long before Bleachers.
7. "House On Fire," Sia 
Sia has made it very clear that she can cough up a handful of hit singles before she even gets her morning coffee, but that doesn't stop her from collaborating with others as well. "House On Fire" made its way onto Sia's latest release This Is Acting, an album compiled of her songs that were rejected by other artists. If this track proves anything, it's that even Sia's bits from the cutting room floor are better than our best efforts. She also made a guest appearance on Terrible Thrills, Vol. 2, the female compilation version of Bleachers' Strange Desire.
8. "Heaven," Troye Sivan featuring Betty Who 
One of the most moving tracks off of his debut album Blue Neighbourhood, Troye worked with Jack to bring life to a song documenting his inner turmoil before coming out as gay in 2013. As he explained in a video on his YouTube channel, "when I first started to realize that I might be gay, I had to ask myself all these questions -- these really really terrifying questions. Am I ever going to find someone? Am I ever going to be able to have a family? If there is a God, does that God hate? If there is a heaven, am I ever going to make it to heaven?"
The end result featured a guest spot from Betty Who, as well as co-writing from Claire Boucher, aka Grimes.
9. "Out Of The Woods," Taylor Swift 
As well as being close friends, Jack and Taylor are also ongoing co-writers for many of Swift's releases. They co-wrote her Golden Globe nominated track "Sweeter Than Fiction," along with a handful of tracks off of 2014's 1989. The two recorded the songs in his apartment, which would normally seem unorthodox, but seems to be where Jack does most of his work. When they won Best Pop Vocal Album at the 2016 Grammys' pre-telecast ceremony, Jack phoned Taylor from on stage to let her know they'd won while she frantically asked him to tell James Taylor she loves him.
10. "Sweetie," Carly Rae Jepsen 
Jack has received a lot of attention for his work with other artists but as he said himself, "Carly was the first, before anyone gave a shit about me." He co-wrote this Kiss b-side alongside Sara Quin of Tegan and Sara and has recently reunited with her in the studio for Carly Rae's still-untitled upcoming project. After the criminally underrated album that was E•MO•TION, it will be interesting to see what Carly Rae and Antonoff give us next.