Shortly after Jennifer Lopez celebrated the 8th birthday [2] of her adorable twins [3], Max and Emme, the hot mom hit the gym looking as toned as humanly possible. Just in case you need proof, Jennifer was kind enough to share a post-workout photo on Instagram [4], and her abs are nothing short of jaw-dropping. "Gotta get it in...#workinonmyfitness #gymtime #cardio #thereIamwithnomakeupagain! Lol," the Shades of Blue actress captioned the shot. Check out the jealousy-inducing snap above, and then see what happened when she made a hilarious appearance on The Tonight Show [5]!