Radar Staff Reporter
The final four American Idol contestants will have one heckuva mentor next week: the biggest pop star in the world (Sorry, Biebs).
The Born This Way singer will mentor the final quartet through Wednesday's show, where they will sing songs written by Jerry Leiber and Mike Stoller, who penned most of Elvis Presley's hits as well as Ben E. King's classic, Stand By Me.
We've also learned that Gaga will perform on the show's season finale, as will legendary singer Stevie Nicks.
American Idol returns Wednesday on Fox at 8/7c. This season's champ will be announced on the show's May 26 finale.