LOS ANGELES — Moomba’s stage might be pint-sized, but Donovan Leitch’s new act is big. It started as a typical night at Voulez Vous — Audrey Bernstein and Apple Via’s Friday night party — with hipsters like Claire Danes, Ben Lee, Monet Mazur, Drew Barrymore, Amanda De Cadenet and Kirsten Dunst slouched in the banquettes, sipping Coronas and puffing on Marlboro Lights. But then the stage lit up to reveal Camp Freddy, the brazenly campy new band Leitch formed with Red Hot Chili Peppers guitarist Dave Navarro, actor Michael Wincott and former Cult guitarists Billy Duffy and Billy Morrison. “We’re the most famous band since Europe,” joked lead singer Leitch as the group launched into T-Rex’s “20th Century Boy.” Russel Steinberg, who appeared as his infamous karaoke alter-ego Johnny Flayva, and Moby joined in for a rowdy rendition of Led Zeppelin’s “Whole Lotta Love.” Then Robbie Williams, who had been smoking and stomping in the wings, jumped onto a speaker and belted out Queen’s “Fat Bottomed Girls,” before introducing Guns N’ Roses legendary guitarist Slash. Leitch and his various rollicking associates will hit Moomba again this summer before taking Camp Freddy to New York. Glam rock may never be the same.