Madge and the Lady: Front Row at Marc Jacobs

"I didn't invite them," said Marc Jacobs Monday night, referring to Madonna and Lady Gaga, his only VIP guests at his show. "Madonna called three hours before and after working with her (on the Louis Vuitton campaign) I couldn't say no."

And considering that Lady Gaga is performing at the party he and V magazine are co-hosting tonight, well, she was an easy yes too when she asked to attend. Madge and her boyfriend Jesus Luz swooped in at the last minute, while Gaga stood by the photographer pit with Jacobs' fiance Lorenzo Martone. Afterwards, the two pop stars talked backstage while models, still in kabuki-esque makeup, snapped photos of them.

Gaga then left to prepare for her performance at Hiro later tonight, which Janet Jackson, Gwen Stefani, Courtney Love and Katy Perry are also expected to attend. "Maybe Marc and I will do a duet," she said.