Katy Perry and Darren Criss Duet on ‘Teenage Dream’ (VIDEO)

The combined musical powers of Katy Perry and Darren Criss, all on one stage? As improbable as it seems, it all went down on Sunday night. And it was for a good cause.

Glee hottie Criss—who’s been known to bust out his rendition of Perry’s tune “Teenage Dream” from time to time—once again belted out the song during Trevor Live, a fundraiser for the anti-bullying Trevor Project, at the Hollywood Palladium. Halfway through the song, Criss was joined by Perry herself.

Check out Perry and Criss’ charitable collaboration below.