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.