Jessica Simpson rang in her 36th birthday on Monday, and to celebrate, she lost her top for a day of sunbathing in the pool. Jessica shared an Instagram photo of herself relaxing on a giant float and drinking out of a gold pineapple, writing, "Kiss My Butt 36." She also showed off her toned backside. Just a couple of weeks before her own big day, Jessica celebrated her lookalike son Ace's fourth birthday with a Moana-themed bash at their LA home. Judging by her latest sexy snap, Jess can certainly still rock a pair of Daisy Dukes (or even less!) like she did in the late '90s.