“A sexy, wide-eyed comedian with a semi-operatic voice,” as the New York Times’s Stephen Holden called her, cabaret star KT Sullivan is coming to Tribeca for four Thursday nights (Aug. 20 and 27, Sept. 3 and 10), taking over one of the private dining rooms at City Hall Restaurant. City Hall, which celebrated its 10th anniversary last October, had hosted Mingus Mondays and a monthly open-mic poetry night in the space, “but it had been a while,” said Robert Palermo, director of private dining. “So when KT Sullivan approached us about a trial run, we were intrigued.”

The building was constructed in 1863 as a shoe factory, and the Granite Room—located beneath ground level—had a dirt floor when City Hall moved in. The restaurant kept certain architectural details (part of the ceiling is granite—it’s the underside of the Duane Street sidewalk—and another part is vaulted brick; the cast-iron pillars are also original) while making it comfortable and intimate. The acoustics are so good that while Sullivan and her accompanist, Jon Weber, were practicing, she decided that she would sing without a microphone. As a result, says Palermo, Sullivan plans on walking the room as she sings.

The nights are billed as “Kathleen Downey’s Granite Room”—Kathleen Downey is Sullivan’s married name—and tickets are $90. That includes a three-course prix-fixe dinner, with a choice of three appetizers, three entrées, and three desserts. Dinner seatings are available from 5 p.m. to 6 p.m., and there’s space for 80 guests. For more information or to reserve, call 212-227-7777.

UPDATE: A few hours after this was posted, KT Sullivan called in response to an emailed request for an interview. The idea for the City Hall engagement came from her friend Sondra Lee, who played Tiger Lily in the original 1954 Broadway production of Peter Pan. “Sondra hates the food at the Algonquin,” explained Sullivan, “and she said, ‘You must find a place to play where the food is good.’ She suggested the Granite Room at City Hall.”

She’s excited about singing without a microphone, because whenever she’s performing she tries to sing at least one song sans mic—”people love it!”—and she’s never done it for an entire cabaret show before. Besides, she’ll be only be singing songs from before 1929, when performers didn’t have amplification: “Early Cole Porter, early Gershwin, early Irving Berlin. Songs from as early as the 1870s. My wonderful pianist, Jon Weber, and I are even doing a medley of 29 songs from 1929. It’s about five minutes long, and we’ve found ways to link the songs together.” There will also be a medley of songs about women named Kathleen, in honor of KT’s given name.

If she’s one-eighth as ebullient in concert as she is on the phone, the audience is in for an enchanted evening.