Darren Criss singing a Christmas duet with Chris Colfer? Very cool.

Darren Criss singing a charity gala duet with Katy Perry? Even cooler!

That's exactly what took place at an event last night in honor of The Trevor Project, a suicide prevention hotline for gay youth. Criss kicked off his rendition of "Teenage Dream" with a few backup singers - but is joined about a minute into the following video by Perry itself. The crowd, understandably, goes nuts:

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.