Tip - 10 Britney Spears Dream Collaborators: Who She Still Needs To Work With

It's Britney (and Iggy), bitch: Britney Spears returned on Monday (May 4) with "Pretty Girls," a new collaboration with Iggy Azalea that marks one of the year's most high-profile single releases. The pairing of Spears and Azalea makes sense -- after all, Spears has been looking for a new radio hit, the Australian rapper is coming off of a huge year, and "Fancy" co-producers The Invisible Men have given the female duo another slinky beat on which to shine.