The season finale of 30 Rock is shaping up to be a musical affair.

And a guest star-laden one. We know you must be shocked at both.

The NBC comedy has lined up a roster of musicians for its season finale on Thursday, May 14. So far, the network says only that the third campaign's finale will be a "special episode featuring Alan Alda (M*A*S*H*, The West Wing) and surprise musical guests."

Alan Alda is scheduled to appear in the season's final two episodes.

In the finale, he'll be joined by music stars Elvis Costello, Sheryl Crow, Mary J. Blige, Clay Aiken and Adam Levine. Sherri Shepherd will also be reprising her recurring role as Tracy's wife.

Whether all those guests will boost the show remains to be seen.

A few of the 30 Rock guests this season - notably Salma Hayek (above), who will be back this Thursday - have blended in seamlessly with the show, but others (Steve Martin, Jennifer Aniston) haven't been as successful and seemed like stunts.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.