“I miss playing with my band,” Ashlee Simpson, 23, confessed to me on Thursday night. I caught up with the younger Simpson sister at The Underground, a local stop on the club tour promoting her latest single, “Outta My Head (Ay Ya Ya).” The club-tour format, popularized recently by pop stars more accustomed to arena-sized crowds (think Madonna and Britney), is designed to help boost an artist’s popularity—or rather, her album sales. According to parent company Rockit Ranch, the show was also a way to “give back” to The Underground’s VIP patrons in honor of the club’s first anniversary. Simpson’s intimate concert was invite-only, as was Kanye West’s show there last summer.

By 10:30 p.m. Thursday the club had hit capacity, and a mob was congregating out front. Both the invited and the uninvited were name-dropping furiously while doormen tried to control the swelling crowd. The club remained packed throughout the night, with people perched anywhere they could grab a glimpse of the uber-petite, auburn-haired rocker. Wearing skinny lavender Ksubi jeans and Nike hi-tops, Simpson performed “Little Miss Obsessive” and “L.O.V.E.,” in addition to “Outta My Head,” during her 20-minute set, with only her guitar player (and ex-boyfriend) Ray Brady and DJ Poet accompanying her. And, yes, she actually sang—no lip-synching—although her voice sounded a little hoarse. Perhaps she should have slowed down on the Stoli Elit she was drinking in a booth with friends before going on. I’m just saying.

The 300 or so attendees seemed less interested in Ashlee’s performance than what she looked like up-close, post nose job (she’s beautiful), and whether big sis Jessica or boyfriend Pete Wentz would show (she didn’t; he did). As promised, I asked Ashlee the questions you posted in response to last week’s blog. “I’m happy as long as my sister’s happy,” she said, cryptically, when I asked her about Jessica’s relationship with Dallas Cowboys quarterback Tony Romo. “They’re sweet. They have a great time together. He just came to Dallas [to hang out with us].” When I realized I wasn’t getting anything juicy out of her, I decided to move on to the tough questions and ask whether she had voted in the California primaries, per one reader’s request. “Um, uh,” she stammered before saying, with a giggle, “Yes, I voted.” So I pushed a little harder and asked if she supported Obama, for whom Wentz hosted a local fundraiser in January. “We keep CNN on all the time,” she responded vaguely. Convincing.

Speaking of Wentz, I bumped into him backstage earlier and asked if he had attended the Grammys. “Nah,” he said. “We watched at home. I thought the performances were just OK, except for Kanye’s.” Later, Ashlee admitted they watched the ceremony in their PJs but did attend some of the pre-Grammy bashes. Her favorite was Clive Davis’s—the one party I can never get into.

If you missed Ashlee last Thursday, you might get another chance to see her live: She told me she’s embarking on a bigger tour with her band in April.

Photography: Barry Brecheisen for WireImage