Miley Cyrus will be this week's "guest-mentor" on American Idol. Miley will help the contestants as they prepare for the show. The theme for tonight's show is Billboard Number 1 Hits.
Miley will also perform her song "When I Look At You" on Wednesday’s results show. Joe Jonas and Demi Lovato will also be performing on Wednesday singing "Make a Wave."
Source: American Idol.