Britney Spears Premieres New Song!

Singer Britney Spears made a guest appearance on Ryan Seacrest's radio show Friday morning to talk about her upcoming album, "Femme Fatale," and to debut her new single, "Till the World Ends.'

The 29-year-old singer told Ryan the song "just has good energy." The track was co-written by fellow pop star Ke$ha and produced by Dr. Luke and Max Martin, who also helmed the album's first hit single, "Hold It Against Me."

Listen to "'Till the World Ends" and the interview with Seacrest!

"Femme Fatale" hits stores March 29.