Aloha, Hilary Duff's bikini body! The actress showed off her insanely toned curves while relaxing on the beach with her son, Luca, and a few friends in Kihei, HI, last week. Hilary, who was put in an awkward position last year when Aaron Carter professed his love for her, wasn't shy about putting her washboard abs, muscular arms, and toned legs on full display in a printed two-piece suit. The star, who also wore a cute floppy hat and sunglasses for the outing, flashed a huge smile as she soaked up the sun and splashed around in the waves on Sept. 3. The day after hitting the beach, Hilary took to Instagram to share a poolside vacation snap with her followers. Keep reading to see more of Hilary's sun-soaked day, then check out her sweetest moments with Luca on Instagram.