So that's why she's been in Hawaii!
The American Oxygen singer was one of the bridesmaids during the event, dressed in a super pale lilac Badgley Mischka gown with delicate floral embroidery.
From far away she almost looked like a bride herself!
Man, how cool would it be to have RiRi at your wedding? We wouldn't even mind if she got most of the attention! Ha!
Check out more photos of Rih and the wedding party in the gallery (above)!
[Image via Ginsburg Spaly.]