Katy Perry Performs 'Teenage Dream' With 'Glee' Newcomer Darren Criss

It looks like the Warblers were living a real-life teenage dream this Sunday (Dec. 5) at the Trevor Project's holiday fundraiser. The newest "Glee" showchoir group, including new favorite Darren Criss, performed their hit rendition of "Teenage Dream" at the Trevor Project's holiday fundraiser -- and was joined on stage by none other than the song's original singer Katy Perry.

Video: Katy Perry Performs "Teenage Dream" with Darren Criss and The Warblers

Perry's version of the song spent two weeks at the top of the Billboard Hot 100 in September, while the "Glee" version -- lead by Criss -- had the best selling debut of any "Glee" single, with 214,000 copies in the first week, according to Nielsen SoundScan.

Glee's Chris Colfer Speaks Out Against LGBT Teen Suicide

The Trevor Project, which is associated with the popular "It Gets Better" celebrity PSA campaign, is a crisis hotline that provides counseling to LGBT and struggling teens.