Mary J. Blige, Clay Aiken Loved Singing For '30 Rock'

Singers had a blast participating in season finale's 'Kidney Now!' benefit show.

Learning that [artist id="1236902"]Clay Aiken[/artist] is the cousin of NBC's most cheerful employee, Kenneth Parcell (Jack McBrayer), was almost as shocking as seeing the rest of the star-studded crowd Jack Donaghy (Alec Baldwin) could coerce into participating in his "Kidney Now!" benefit concert on the season finale of "30 Rock."

In the episode, Aiken and a slew of famous faces, like [artist id="854"]Mary J. Blige[/artist], Sheryl Crow, Elvis Costello and Cyndi Lauper, joined in Jack's effort to find a kidney donor for Milton Greene (Alan Alda), the man who may or may not be his father. Aiken says it was an honor to be involved.

" '30 Rock' is not only the funniest show on TV now; it's also the smartest," Aiken told MTV News in a statement. "Things that you see or hear on that show start popping up in everyday life all of the time. I don't think any show since 'Seinfeld' has been able to do that."

Like "Seinfeld," these days Liz Lemon and her motley crew leave the "American Idol" alum in stitches every week. " 'Seinfeld' had 'yada, yada, yada' and 'master of your domain.' '30 Rock' has "That's a deal-breaker, ladies' and many more. I find myself saying 'What the what?' all of the time. They've really broken into the zeitgeist like no other show has."

Given the subtle reveal of Aiken's newfound "cousin," it sounds like the "Spamalot" star might have an opening to return for another stint.

Blige also loved the experience of guest-starring on the show. "I had so much fun!" she told MTV News. "Everyone was so nice and respectful of each other, and it felt like family. I couldn't stop laughing in-between takes. I was sad when I left; I wanted to come back the next day."

In case you missed it, the episode's "We Are the World"-style benefit show also included Adam Levine, Beastie Boys Mike D and Ad-Rock, Michael McDonald, Sara Bareilles, Wyclef Jean, Norah Jones, Talib Kweli, Rhett Miller, Moby, Robert Randolph, Steve Earle and Rachael Yamagata.

And it turns out their efforts weren't just for laughs. In real life, proceeds from iTunes purchases of the song will help benefit the National Kidney Foundation.