If Rob Lowe ever needs a body double for an upcoming role, he can definitely just use his son! The actor, who turned 52 on Thursday, took to Instagram to share a photo of him and his look-alike son, John, on his big day. In the snap, the two pose shirtless while staring at the camera. "Celebrating my #birthday With a #workout and @johnnylowe Whatever your age, be your best! #men #results @profile4men," he wrote.