"I don't know when she's getting married, but I'll be there," the bride's bandmate told PEOPLE at the Bloomberg afterparty for Saturday's White House Correspondents' Association Dinner in Washington, D.C. "I got a wedding gift for her and Josh – some new beats, so she can sing over them!"
Besides the bride, will.i.am also gushed about Duhamel, calling the Las Vegas star "super-duper cool – one of the nicest guys I've ever met."
Good thing, too, because he says he considers Fergie, 33, "my little sister. They're perfect for each other. She brings out the best in him and he brings the best out of her."
So what kind of spouse will the Duchess – who became engaged to Duhamel, 35, in December – be?
"She's Fergie-Ferg, she's just cool," says will.i.am, also 33. "That's like the coolest wife you could have, right?"