Rumer Willis debut short blonde hair Credit: Justin Campbell

Who's that girl!? Rumer Willis has taken on a new look for the rest of summer. Bruce Willis' 25-year-old daughter debuted a blonde bob at Just Jared's Summer Fiesta at Pink Taco in West Hollywood on Saturday, July 12.

Ditching her long pink strands, Rumer rocked her new blonde 'do, along with heart-shaped sunglasses, looking more grown-up than ever at the fete, which was sponsored by Aerie.

Demi Moore's eldest daughter posted an image of her new locks on Instagram that same day, shouting out hairstylist Dominick Serna with the caption: "Love my new hair do coursty of @domdomhair captured by the main man @thetylershields."

Photographer Tyler Shields shared the same artistic snap of Rumer, with the simple caption, "@ruelarue hair."

Tell Us: What do you think of Rumer's new 'do?