Passenger

This guitar-driven song finds a vulnerable Spears ruminating on romantic trust as she lets go of the hesitation that comes with a new relationship. She sings: "I'll let you the lead the way now, cuz I want you to take the wheel I've never been a passenger Though, I never knew how good it would feel." The track was written by Katy Perry - presumably inspired by recent events in her life - along with Australian singer-songwriter Sia. Perry also wrote about her failed marriage with Russell Brand on her Prism album, as well as songs about finding love again with John Mayer.

Spears told MTV News how the collaboration with Perry came about. "We actually didn't get in the studio together," she explained "My people and her people worked it out, but I'm a huge fan of hers. I think she's an amazing vocalist and she has a beautiful voice. And I love the song. From the moment I heard the song, I was like, 'This is really beautiful.' So I was really proud I was able to do it."