Back in February, he said: "I don't think I ever took my shirt off in a pool until I was in my mid 30s even in front of family and friends.
"Probably would have happened sooner if my childhood insecurities weren't exacerbated by years of public mockery about my body."
He also urged people with their own insecurities to "have fun" and know they are "awesome and perfect".
He continued: "I'm 37 and finally love and accept myself. This isn't a 'good for me' post. And it's definitely not a 'feel bad for me post'.
"It's for the the kids who don't take their shirt off at the pool. Have fun. You're wonderful and awesome and perfect. All my love. (sic)"
Meanwhile, the 21 Jump Street star previously said he is grateful to his friends and family for allowing him to openly discuss his own vulnerabilities.
He said: "As I've grown up as a human being, and have had the emotional maturity and confidence to become a filmmaker, [I've reflected on] how I learned to communicate as a man and why that was problematic.
"I was taught and maybe culturally we were taught at that time, if you're a man and you express your feelings or you express that something hurts you, then you should be made fun of.
"And that kind of repression leads to anger, and anger leads to bad behaviour."