Britney Spears’ ‘Till The World Ends’ The Latest Track Written By A Fellow Pop Star

On Friday morning (March 4), Ryan Seacrest woke up after a big night of “American Idol” madness to host his daily radio show, which featured an extra-special guest in the studio. Britney Spears stopped in to chat about her upcoming album Femme Fatale and to premiere the full version of the new song “Till the World Ends,” another top-shelf dance track from the album. After staying out of the spotlight for a while, Spears now seems to be ready to come back in to the universe, as she did this interview, premiered the video for “Hold It Against Me” and appeared on the cover of V magazine all in about a 10 day span.

“Till the World Ends” is a great addition to the album, and it’s an interesting track because it was written by fellow pop star Ke$ha. While it may seem odd that a radio staple would create a new song for somebody who is ostensibly a competitor, it happens all the time (especially lately). Here are some other stars who have no trouble crafting tunes for fellow stars.

Katy Perry
Perry is currently tearing up the charts with her album Teenage Dream (fourth single “E.T.” just shot up the Billboard Hot 100 and is about to see its video premiere), but she has also lent her skills out to other singers — specifically to Kelly Clarkson, whose “I Do Not Hook Up” (from 2009′s All I Ever Wanted) was co-written by Perry.

Keri Hilson
Hilson has scored hits for herself in tracks like “Knock You Down” and “Pretty Girl Rock,” but her fingerprints are all over a lot of other singers’ tracks. Her writing credits include songs for Britney Spears (“Gimme More”), Pussycat Dolls (“Wait a Minute”) and Ciara (“Like a Boy”).

Ne-Yo
Ne-Yo’s voice has been on a number of big hits (including 2006′s chart-topping “So Sick”), but his pen has lent magic to songs like Beyoncé’s “Irreplaceable” and Rihanna’s “Take a Bow,” as well as tracks for Whitney Houston, Celine Dion and Enrique Iglesias.

Taylor Swift
Swift’s songs are so personal that it seems like they wouldn’t function outside of her own universe, but that didn’t stop Swift from co-writing “Best Days of Your Life” with Pickler for her self-titled 2008 album.

The Jonas Brothers
Between their own band and their various solo projects, Nick, Joe and Kevin Jonas are pretty prolific. They also lent a hand to friend Demi Lovato, co-writing the bulk of her debut album Don’t Forget (and Nick Jonas also co-wrote a tune on Lovato’s 2009 follow-up Here We Go Again).