Michelle Obama - Michelle Obama Spends Sunday At Gwen Stefani's House

As part of a two-day trip to Hollywood, where Obama will be raising funds for her husband's re-election campaign, Stefani's new pal helped with face painting and balloon sculptures as well-off families enjoyed an afternoon with political royalty.

Families of four paid $2,500 (£1,500) for the chance to rub shoulders with the celebrity co-hosts at the home Stefani shares with husband Gavin Rossdale and their young sons.

The First Lady thanked guests for digging deep to attend the party, telling them, "Barack can't do it alone. He's not Spider-Man. He's not a superhero. He's a human, so we need your help. I am not just talking to the adults here today. I am talking to the young people here as well.

"All of our young people - you might not be old enough to vote. You vote at school, I know - I met several young people who are going to be voting for my husband... We accept those votes. You can play an important role in this election, too. I want you all to feel empowered."

And Stefani's bandmates were thrilled to meet Obama - drummer Adrian Young and guitarist Tom Dumont both took to Twitter.com to chat about getting up close to the First Lady.

Young wrote: "Life in (No Doubt) land gets more strange and wonderful everyday," while Dumont called Obama "so warm and sincere".

Among the other celebrities at the party: Nicole Richie and her husband Joel Madden and actress Alyson Hannigan.