Gwen Stefani and her husband Gavin Rossdale hosted a fundraiser at her Los Angeles home over the weekend, which was attended by First Lady Michelle Obama.
Other celebrity guests included Nicole Richie and her husband Joel Madden and actress Alyson Hannigan.
Obama is spending two days in Hollywood to raise funds for President Barack Obama's re-election campaign, and families of four spent $2,500 to attend the party, which included face painting and balloon sculptures.
The First Lady told guests, "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."
Stefani's No Doubt bandmates, drummer Adrian Young and guitarist Tom Dumont tweeted about the event. Young wrote: "Life in (No Doubt) land gets more strange and wonderful everyday," while Dumont called Obama "so warm and sincere".