Watch Ashlee Simpson’s Surprise Performance Of Her 2004 Hit La La With Demi Lovato!

Ashlee Simpson Returns to the Stage for "Lala" Performance With Demi Lovato

Watch Ashlee Simpson Make a Rare Return to the Stage to Perform With Demi Lovato

Ashlee Simpson Joins Demi Lovato Onstage For a Surprise Performance of Her Hit 'Lala'