The Blaine of 'Glee' and Keenan are joined by Harry Shum Jr., Dianna Agron, Darren Criss and Jenna Ushkowitz in doing the silly rendition of the Katy Perry song.
Darren Criss and his "Glee" co-star had a lot of fun with YouTube lip-sync star Keenan Cahill at what looks like to be the backstage of their concert. They mime Katy Perry's "Last Friday Night (T.G.I.F)" and do some fun dancing to the upbeat music.
The "Glee" actors who help make the lip-sync rendition more fun are Harry Shum Jr., Dianna Agron and Jenna Ushkowitz. At one point, Dianna pretends to be playing some invincible drums, while Darren is playing a fake saxophone.
"Glee" stars have just wrapped up their 2011 summer tour. Kicking it off on May 21 in Las Vegas, they ended the traveling show on Sunday night, July 3 at The O2 in Dublin, Ireland. At the final show, Darren surprised concertgoers by kissing Chris Colfer, and Naya Rivera sent them into frenzy by smooching Heather Morris who plays her on-screen love interest.