Just when we were starting to warm to Rumer Willis‘s new ‘all-grown-up’ look, she goes crazy with a bottle of peroxide! Bruce and Demi’s daughter giggled furiously at the opening of James Perse store in Beverly Hills last night, telling anyone who’d listen: "I’ve always wanted to be blonde!" Rumer even changed her look mid-evening and greased back her new goldilocks for another event later last night.