Set your DVRs tonight, Miley Cyrus fans—the pop star steps up as this season's first celebrity guest mentor on American Idol! The top 11 contestants will sing a selection of Billboard No. 1 hits, and who better to help them out than Miley, the youngest multi-platinum recording artist to have four No. 1 albums in less than three years. Tonight we'll see her individual sessions with the contestants—16-year old contestant Aaron Kelly tweeted: "The mentor was incredible. What an honor to meet someone with so much experience." Miley will perform her hit single "When I Look At You" on tomorrow's results show. Fellow pop sensations and new couple Joe Jonas and Demi Lovato will also treat the audience to a performance of "Make a Wave." American Idol airs tonight at 8 p.m. on Fox.