TV and Broadway star Megan Mullally will extend the full-scale production of her one woman show Sweetheart at the Coast Playhouse in West Hollywood through Dec. 11. The show was set to close Nov. 20 after beginning performances Oct. 14 with an opening night Oct. 23.

Sweetheart started with a few fewer performances than originally scheduled. Instead of previewing the solo show Oct. 7, Mullally had to change the date to Oct. 14 due to a scheduling conflict, according to a spokesperson.

Sweetheart is Mullally's exploration of relationships, from both male and female perspectives. Using 12 well-known and obscure story songs, she covers the idea of a "sweetheart" in moods that range from dark to tongue-in-cheek.

"I have to call it performance art," Mullally said (at the time of the workshop), as opposed to calling Sweetheart a cabaret or a club act. In the piece, the three men in the band and herself "discover" the theatre space and the audience around them. Mullally sometimes even serves as sound technician, playing music for herself on a boom box and giving sound cues.

For Mullally, who directed and wrote the piece, Sweetheart is a chance to sing songs she has always loved in a way that she finds challenging. "I thought, 'How could I perform these songs'? I don't want to just stand up in a club and sing them. They deserve better than that," she said. In fact, she's less interested in simply making the songs sound pretty than using them as performances pieces. She explains that "it's more like acting in pitch."

Part of her "pitch acting" involves taking traditional song interpretations and turning them on their ear. One such song, the near-lullaby "Scarlet Ribbons" starts out like a children's nursery rhyme, as a mother describes hearing her child pray for scarlet ribbons which miraculously appear on the child's bed the next morning. Mullally, on the other hand, reduces the mother to a frightened lunatic losing control of her mind as she suspects the forces of evil have arrived with the ribbons.

Several of Mullally's songs are taken from theatre sources, including Richard Rodgers and Lorenz Hart's "10 Cents a Dance" (Simple Simon, 1930), Kurt Weill and Maxwell Anderson's "It Never Was You" (Knickerbocker Holiday, 1938), Stephen Sondheim's "Johanna" (Sweeney Todd) and "I Remember" ("Evening Primrose") and Weill and Bertolt Brecht's "Surubaya Johnny" (Happy End). Other songs range from the anonymous ("She Is My Slender" and "In the Gloaming") to traditional American folk songs (Stephen Foster's "Beautiful Dreamer") to the pop of Randy Newman ("Marie," "Guilty") and Tom Waits ("Ruby's Arms").

Currently seen on NBC as Karen Walker in "Will And Grace," Mullally made her Broadway debut as Marty opposite Rosie O'Donnell in the 1994 revival of Grease. She returned as Rosemary Pilkington in the 1995 revival of How to Succeed in Business Without Really Trying starring Matthew Broderick. Other television and film credits include "Seinfeld," "Mad About You," "Frasier," "About Last Night" and "Queen's Logic."

Also on board are Greg Kuehn (musical director), George Barker (lighting designer) and John Clemens (sound designer). Kuehn, Mathis and Berardi serve as the band as well.

Mullally did a workshop mounting of Sweetheart at the Coast this past spring.

Tickets are $15-$25 and available by calling Tickets L.A. at (323) 655 TKTS. The Coast Playhouse is located at 8325 Santa Monica Boulevard.

-- By Christine Ehren and David Lefkowitz