Rob Lowe's son John, 29, is an actor just like his father, ... "If Johnny wasn't in this picture I would expect him to totally roast his dad for posting in it," another person added.

Rob Lowe shares his candid thoughts on posting 'thirst traps' in an exclusive interview with PEOPLE. The actor, 61, posted a shirtless gym selfie with son John Owen, 29, last month.