Adam Lambert stood in for Freddie Mercury at the 2013 iHeartRadio Music Festival, where he performed with Queen -- and also with Fun.!

The 'American Idol' alum can hit all of Mercury's high notes, though clearly their actual voices -- save for their multi-octave ranges -- are unique. The 'Trespassing' singer shined particularly brightly on 'Who Wants to Live Forever.' (You can see that above!) We bet his performance gave Glamberts chills!

After delivering a handful of tracks with the rock legends, Lambert left the stage and let Nate Ruess and Fun. fill his (and Freddie's, obviously) particularly large shoes. Ruess was clearly pretty nervous (because, dude, it's Queen), but he held his own, especially during 'Somebody to Love.'

A moved Ruess shouted, "Thank you to Queen for making this dream come true!"

To close the band's set, Lambert returned to the stage with Ruess to deliver a soaring rendition of "We Are the Champions." And of last night? They absolutely were.

You can see the full performance here.