Sources tell Billboard.com the pop star will reportedly sing Somebody to Love and Fat Bottomed Girls during the group's performance at the event, which will be held at the MGM Grand Garden Arena.
He'll share the mic with Adam Lambert, who became Queen's regular stand-in singer last year (12).
Ruess will also hit the stage with fun. on Friday night (20Sep13), when Katy Perry, Elton John, Keith Urban, Muse, Tiesto and Chris Brown will also perform.
Paul MCCartney, Justin Timberlake, Drake, Miley Cyrus and Bruno Mars will be among the stars headlining the event on Saturday (21Sep13).