Viral video star Keenan Cahill is back with another lip synch, this time adding the power for the "Glee" cast.
Stars Dianna Agron, Jenna Ushkowitz and newly minted cast regulars Harry Shum Jr. and Darren Criss joined Cahill backstage during the "Glee Live" arena tour to record a video to Katy Perry's "Last Friday Night (T.G.I.F.)"
Criss is the only Gleek to who seems to know all the words to the hit, probably thanks to his cameo in the official music video.
HuffPost Entertainment is your one-stop shop for celebrity news, hilarious late-night bits, industry and awards coverage and more — sent right to your inbox six days a week. Learn more