LOS ANGELES -- Nancy Sinatra appearing onstage with the Brit-pop Wondermints was one thing.

But when Beach Boys legend Brian Wilson hopped up there to join these relatively obscure headliners during their set Tuesday at the Spaceland nightclub here, the Christmas-season gathering turned into a virtual beach party.

Considering the heat generated in and out of the club, and the surf rock blaring over the PA between sets, one might have been fooled into thinking it was summer.

Wilson and the daughter of the late crooner Frank Sinatra were the special guests for the Wondermints' performance at the intimate spot. Taking the crowd by surprise, the special guest stars helped turn what otherwise would have been a night of pure pop into a retro-flavored affair that had young and older patrons bouncing and screaming.

The Wondermints --Darian Sahanja (vocals/keyboards), Nick Walusko (guitar/vocals), Michael D'Amico (drums/vocals), and David Nolte (bass) -- are possibly best known for the theme song from "Austin Powers: International Man of Mystery." But that may soon change, as they are scheduled to join Wilson as his backing band next year on his first solo tour, promoting his latest album Imagination.

"I've loved them for at least five or six years now," concert-goer Kari Hartkorn, 25, said about the Wondermints. When asked whether she was excited about their getting to tour with Brian Wilson, Hartkorn added, "Of course! I'm going to New York to see them in February."

The musicians will appear together on the East Coast from Feb. 10 through March 10. Then they will head off to Japan and England before returning to North America for summer and fall jaunts.

The Wondermints' following was boldly represented Tuesday by throngs of Brit-pop types clad in polyester dresses and bell-bottomed denim. The band bopped its way through a set that included tunes from its self-titled 1995 debut album, as well as its latest LP, Bali (available now only on import in the U.S.). The set list featured the irresistible opener "Hypnolove," "Bubbles," the absolutely lovely crooner "Tracy Hide" and dance-pop nuggets "Puppet Girls Are Go" and "Proto-Pretty."

But things took a turn for the best about halfway through the act when Sahanja introduced "some heavy friends" to the crowd. Prior to that, the audience had been abuzz about the rumored surprise appearances.

When Sinatra took the stage, accompanied by two male singers, the audience responded with whoops and hollers.

As she broke into her classic, "These Boots Are Made for Walking" (RealAudio excerpt), the Wondermints backed her with surging keyboards and a rousing trumpet solo, which only seemed to inspire the crowd to holler more.

Wilson, one of pop music's icons, needed no introduction. Just his presence inspired thunderous applause, as he performed Beach Boys classic "Do It Again" (RealAudio excerpt).

Then he hopped off the stage and disappeared into the night, with Sinatra in tow.

As the Wondermints' closed the show with "Playtex," actor Dave Foley ("A Bug's Life" and TV's "News Radio") lamented his missing the show's highlight.

"We came to see The Wondermints, and it would have been great to see Brian and Nancy, but we got here too late," he said. "I've had a blast, though! ... The Wondermints are so cool!"