Songwriter: Jessie J

Before she rose to fame as a solo artist, Jessie J wrote one of Miley Cyrus' biggest hits, which peaked at No. 2 on the Billboard Hot 100 chart. She told Glamour U.K. in 2014 that she had originally written the song for herself with Dr. Luke and Claude Kelly, but ended up not recording it. She said the song ended up paying her rent for three years.

Songwriter: Ed Sheeran

Sheeran penned "Love Yourself" from Bieber's Purpose album, then he had Bieber on his own No. 6 Collaborations Project on the track "I Don't Care."

Songwriter: Ed Sheeran

Sheeran also contributed to K-Pop sensation BTS' 2019 album, Map Of The Soul: Persona, with the song "Make It Right."

Songwriter: Julia Michaels

Julia Michaels has now made a name for herself as a solo artist, but she started out writing hits for other artists for a minute. She penned Justin Bieber's "Sorry" for his Purpose album, arguably the album's biggest hit.

Songwriter: Christina Milian

Try not to let this blow your mind, but Christina Milian is responsible for Justin Bieber's first hit. Yes, it's true. She wrote "Baby." She did that. Bieber has Usher to thank for discovering him, but he owes a heck of a lot to Milian.

Songwriter: Ne-Yo

Beyoncé doesn't write a lot of her own songs. Lots of mainstream artists don't, honestly. But Ne-Yo does! The "So Sick" singer wrote Queen Bey's early classic "Irreplaceable," and reportedly regretted selling it afterwards. I would too! That song's iconic.

Songwriter: Sia

Shine bright like... all the money Sia has in the bank thanks to writing Rihanna's "Diamonds." The devil works hard, but Sia works harder.

Songwriter: Pharrell Williams

I'm going to let you in on a little secret: Pharrell Williams is behind just about every iconic song you could think of. The list gets even more overwhelming when you factor in the songs he produced. Gwen Stefani's "Hollaback Girl" is one of countless hit songs he penned.

Songwriter: Sia

Pharrell Williams and Sia have a lot in common in that they've grown successful for writing songs for big-name artists. Sia wrote "Pretty Hurts," the opening song to Beyoncé's 2013 self-titled album.

Songwriter: Avril Lavigne

I'll spread my wings and I'll... buy a song from Avril Lavigne! Clarkson's 2004 hit was actually written by emo queen Avril Lavigne. And then it was featured in The Princess Diaries 2. Yes, I remember that. No, I feel no shame.

Songwriter: John Legend

John Legend wrote this classic hit with will.i.am of The Black Eyed Peas.

Songwriter: Taylor Swift

Swift returned to her country music roots to pen Little Big Town's "Better Man" in 2016.

Songwriter: Bruno Mars

Before he was a solo artist with an Album of the Year win under his belt, Bruno Mars penned Ceelo Green's stupidly catchy "Forget You."

Songwriter: Solange

Bey likes to keep it in the family. Solange Knowles actually wrote a lot of songs on Beyoncé's past albums! She wrote "Get Me Bodied" (and was featured in the music video), "Upgrade U," and "Why Don't You Love Me" for her older sister.

Songwriter: Kesha

Kesha is a pop star in her own right, but she wrote "Till The World Ends" for the Princess of Pop herself.

Songwriter: Pharrell Williams

Who freaking knew that Pharrell wrote "I'm A Slave For U?!" He also wrote Snoop Dogg's "Drop It Like It's Hot," Nelly's "Hot In Herre," and Kelis' "Milkshake." The talent this man has. The power this man has. The cultural impact this man has made.

Songwriter: Ed Sheeran

Ed Sheeran is behind a lot of your favorite One Direction songs, "Little Things" being one of the not-so-little hits. Sheeran also wrote "18," "Moment," and "Over Again" for the group.

Songwriter: Ed Sheeran

Sheeran continued his One Direction legacy by writing Liam Payne's debut solo single, "Strip That Down."

Songwriter: Pharrell Williams

Did you think we were done with the Pharrell credits? Think again! Pharrell blessed Justin Timberlake by writing "Rock Your Body" and "Señorita" for Timberlake's debut solo album, Justified.

Songwriter: Julia Michaels

Michaels wrote the bop that is "Bad Liar," Selena Gomez's 2017 single. She also wrote Gomez's "Hands To Myself." Now that she's a successful solo artist, I guess Michaels could stop writing hits for other artists. I mean, she could, but why would she want to?

Songwriter: Calvin Harris

Rihanna found love in a hopeless place on her 2011 9x-platinum single, but it may not have been inspired by her own romantic endeavors after all. It was actually penned by Calvin Harris, who also appeared in several scenes of the music video.

Songwriter: Lady Gaga

The Pussycat Dolls’ song “Elevator” took their career to new heights, but what some fans might not have known is that the lyrics were the work of Lady Gaga. Yep, Little Monsters might take an extra liking to the song after learning that fun fact.

Songwriter: Julia Michaels

Julia Michaels has written or co-written for dozens of artists aside from herself, including Fifth Harmony. The songstress penned the girl group’s 2013 song “Miss Movin’ On,” written about finding independence after a broken relationship.

Songwriter: Julia Michaels

Michael’s long list of credits includes some seriously impressive names, and Lovato is undoubtedly one of the biggest artists she’s written for. Michaels lent her skills on the pop star’s 2013 year track “Fire Starter.”

Songwriter: Pink

Lambert’s “Whataya Want from Me” took over airwaves upon its 2009 release. While the American Idol alum is an incredibly talented songwriter, even he gets a little help from friends. Pink was the mastermind behind this particular single.

Songwriter: Drake

If you take a look at the songwriting credits for Key’s “Unthinkable,” they include the name Aubrey Graham, better known as Drake.

Songwriters: CeeLo Green & Busta Rhymes

It was not one, but two, superstar songwriters who hit the studio to write “Don’t Cha” for the Pussycat Dolls. CeeLo Green and Busta Rhymes teamed up to pen the song for the now-defunct girl group.