The "Glee" club rocks and really rolls on tonight's episode of the new hit FOX series when each member of the club is required to spend three hours in a wheelchair -- and also learn a musical number that has them dancing in the chairs.

ET caught up with the cast at AOL studios in New York City as they did interviews for PopEater, JSYK, and AOL Television to find out just how hard it was for them to adjust to seeing life from a chair.

"We were all struggling going up the ramps, being sore a day after we started rehearsing, and we actually had to use arm muscles in this," says Kevin McHale, who plays Artie, who is the wheelchair-bound student on "Glee."

"[When they said], 'Take five,' I heard whack. And we turn around and [Amber Riley, who plays Mercedes] is on the floor," says Cory Monteith, who plays high-school hottie Finn. But the cast also admits that almost all of them fell out of their chair at some point.

"I grew up a ballerina," Dianna Agron, who plays cheerleader Quinn, tells ET. "I don't really have arm muscles. It was so tiring. There was one corner … I was already going over it wrong and I thought I might fall. Our choreographer said, 'Shelby, just drink your juice. Come on, get it going.' Now I am called Shelby every time I am tired."

Also in the episode Rachel (Lea Michele) and Kurt (Chris Colfer) have a Diva-Off, when the oh-so-out Kurt insists he has the right to sing a girl song: "Defying Gravity" from Wicked.

"'Defying Gravity' is my favorite song of all time, I think," Chris says. "In the show, we compete to see who will sing the song . I was venting to [creator/exec producer] Ryan Murphy one day about how, when I was in high school, no one would let me sing that song because they said it was a girl song."

The next thing Chris knew, his real-life experience turned up in the script -- but with a twist.

Tune in to "Glee" tonight on FOX at 9 p.m. to find out who is the true diva. And for more interviews from the cast, check out AOL.com.