and A. J. McLean — original member Kevin Richardson left the group — were the headliners at 99.5 FM’s “Lil Black Dress” Holiday Party.

But the boy band left some partygoers disgruntled. It sang two severely truncated versions of two songs, then split. “They were gone in 10 minutes,” said one source on the scene. “They lost quite a few fans tonight.”

Speaking of fans, that was MSNBC’s Tucker Carlson taking in the Grateful Dead tribute band Dark Star Orchestra this weekend at 930 Club. “I first saw the Grateful Dead in San Francisco in 1984, and many times after that,” Carlson told us. “DSO is what they’d sound like if Jerry [Garcia] had never done heroin. They’re fantastic.”

And in upcoming celebrity news:

» Morgan Freeman will speak at the National Press Club on Dec. 18 on his work for the Grenada Relief Fund.

» Fashion designer Lela Rose, for whom first daughter Barbara Bush has interned, will appear at a champagne luncheon Thursday at Bloomingdale’s in Chevy Chase. Rose is best known for dressing celebrities as varied as Michelle Pfeiffer, Chloe Sevigny and Mariska Hargitay.

» “Project Runway” Season 4 contestant Jack Makenroth will model in the Diesel runway show to celebrate the Universal Gear D.C. boutique opening Friday on 14th Street.

» And “Quantum Leap” star Scott Bakula will sing at Ford’s Theatre on Jan. 18 in a special benefit performance.