The show was facing a serious gap with Jane Lynch moving over to "Glee." But Mullally knows how to improvise, so this could be a good addition. Announcement after the jump.

The official word:

Starz keeps the “Party” hopping and the laughs flowing with the addition of one of television and film’s most beloved comediennes, Megan Mullally, to the cast of the crowd-pleasing original comedy series, “Party Down,” Starz Media EVP Originals Productions and Development Bill Hamm announced today. Production on the second season begins in mid-September in Los Angeles. The half-hour comedy about a Los Angeles catering team – Hollywood wannabes stuck working for tips while hoping for their big break — is tentatively scheduled to return to the air on Starz in April of 2010.

Mullally (“Will & Grace,” Fame) will play Lydia Dunfree, a middle-aged refugee from a lousy marriage who leaves small town life to move to Hollywood where her 13-year-old daughter Escapade hopes to make it as an actress. While the younger endures the audition process, her naïve and eternally optimistic mother Lydia feels honored just to be among the show business “pros” of the Party Down catering company. Her search for Mr. Right only complicates matters for Lydia, but ups the laughs on the show.

She joins a talented ensemble of actors on the comedy, labeled “a must-see” by USA Today and called “straight-up funny” by Entertainment Weekly. As the first season ended, Ron Donald (Ken Marino), the aggressively dysfunctional former leader of the Party Down Catering company, was headed off to manage a Soup N’ Crackers franchise; leaving one-time actor Henry Pollard (Adam Scott) to fill the void as leader; Roman DeBeers (Martin Starr) a self-proclaimed Sci Fi visionary, was still trying to get his screenplay noticed – by anyone; while actor, musician and all round cute guy Kyle Bradway (Ryan Hansen) landed a role in an upcoming action film; and Henry’s flame Casey (Lizzy Caplan) left him at the catered altar to do a few months of stand-up on a cruise ship.

Also returning for the second season are the show’s creators and executive producers: Rob Thomas (“Veronica Mars,” “Cupid”) along with John Enbom, Paul Rudd and Dan Etheridge. Starz Media, the production and distribution sibling of the Starz premium entertainment channels, is producer of the series.

“I’m so excited to be joining ‘Party Down,’ one of my favorite TV shows,” Mullally said. “I’m a big fan of the series and really thrilled to have an opportunity to work with such a terrific cast and talented group of writers.”

“Megan is quite simply one of the most talented actresses in the entertainment business today,” Hamm said. “Her impeccable comic timing and multi-faceted acting skills make her a great fit for the show, and we can’t wait to see how she interacts with the show’s terrific cast.”