Hot Celebrity Butts -- Guess Whose Boat Buns!

Can you guess which sexy singer-actress put her boat buns on full display in this eye-popping shot?! We'll cover the bases and get you started, but then it's on you to "land ho!"

Above the surface she enjoys vacaying and riding the waves in her bikini, but under the sea, she collects thingamabobs. She and her sister are quite the singing duo!