NEW YORK CITY, New York (NBC) - The cast of the acclaimed NBC show will be working without a net for tonight's episode, which airs live with separate performances for each coast. It's old hat for "Saturday Night Live" vets Tina Fey, Alec Baldwin and Tracy Morgan, but a bit daunting for other cast members.

"It's going to be a lot of fun and I think it will be fun for us to do a show in front of a live audience," said Fey, who plays the geeky show runner, Liz Lemon. "It would be nice to prove people actually would laugh. We could be proven wrong," she said.

Jack McBrayer, who plays Kenneth Parcell, a goofy but lovable page, says that the experience "will be invigorating" for the cast, but as the same he's "scared to death."
"A knee-jerk reaction is to swear," McBrayer said. "I'm kinda worried about swearing."

The show airs in its regular time slot of 8:30 p.m., though the West Coast version will be modified with some California-specific jokes tossed into the equation.

"So much can go wrong," Fey told reporters who gathered this week at the iconic building that give the show its name.

"I just don't want to be the first one to make a mistake," said Jane Krakowski. "Well, there's Tracy."

Indeed, Morgan might seem like the most likely choice to go off the rails with some spontaneous hilarity, given his penchant for improv. But he downplayed his own unpredictability.

"I read the script and I know my lines...I'm going to disappoint a lot of people." Added Morgan: "We are all experienced professionals. We are going to have a good time."

Famous for its cameos, with Matt Damon, Queen Latifah and Paul Giamatti among this year's guest stars, the real-time show could surprise with star power.

"Bill Murray is coming in," joked Morgan. "Bill Cosby is supposed to show up. Big Bird is coming."

Damon and Mad Men star Jon Hamm are widely rumored to be on tap for the live show.

Fey said her character, currently in a romantic storyline with a character played by Damon, will be involved in a story where everybody forgets her 40th birthday. Meanwhile, Baldwin's character, Jack Donaghy, is trying to give up drinking while his fiancee is pregnant.

The cast has had to cram for this week's episode. Shooting usually takes place over several days, but this time the team did three practice run-throughs on Wednesday and will have a dress rehearsal before the two live shows. In another switch, they're doing the show at the real "30 Rock," instead of in a studio on Long Island.

But the real adjustment, said Krakowski, is getting everything in one take.

"Another character is going to be there and that's the live audience," she said, "and it does change the timing."

On KKCO, the live broadcast begins at 7:30pm, mountain time.