'Burlesque': Christina Aguilera premieres the movie's lead single, 'Express'

We've only heard snippets from the newly separated pop star and actress Christina Aguilera's lead single from her upcoming film, "Burlesque" titled "Express."

Now, Ryan Seacrest has the official world premiere of the song in its entirety. It's the first of eight new songs to burst from the diva's pipes for the motion picture soundtrack that will also include two new singles from co-star, Cher.