Keenan Cahill is at it again.

The viral video star has posted many videos lip-synching to popular songs, often with celebrities giving him an assist. In his latest effort, Cahill is joined by a few members of the cast of "Glee" - Darren Criss (Blaine), Dianna Agron (Quinn), Jenna Uskowitz (Tina) and Harry Shum Jr. (Mike) - as they dance and mouth the words to Katy Perry's "Last Friday Night (T.G.I.F)."

Keenan is a teenager from Illinois who suffers from Mucopolysaccaridosis, a rare genetic disorder. He has previously been joined in videos by Katy Perry, 50 Cent and others.

Watch Darren Criss and Kevin McHale (Artie) in Katy Perry's "Last Friday Night" Video. Feel free to read our Glee Weekly Recaps. Join us on Twitter @soapoperafan, and Facebook. Come tweet and Facebook with us about all soap operas, "Glee," "Grey’s Anatomy" and "Vampire Diaries!"