'Fast & Furious 6' star Dwayne 'The Rock' Johnson posted a photograph on Twitter after he met with prison inmates and encouraged them to "stay strong".The 'G.I. Joe: Retaliation' star posted a photo on his Twitter account yesterday (12.06.13) showing his meeting with inmates and wrote an inspirational message noting how he overcame his own spells in jail to become a success.He said: "I was arrested multiple x's [times] as a teen (fighting/stupid s**t) Said if I can make it, so can you. Stay strong #LockUp. (sic)"The 41-year-old actor has spoken before about his past and has explained he didn't see the "potential" he had until years after his "eight or nine" teenage arrests.He previously revealed: "I got in trouble a lot when I was younger. By the time I was 16, I had been arrested eight or nine times for a variety of things, terrible things that I shouldn't have been doing."Much later in life, once I got out of college, I started to understand the power of seeing your potential and what that means."Dwayne's Hollywood friends have spoken of their admiration for the WWE superstar's work ethic, with his 'Fast & Furious 6' co-star Gina Carano commending his dedicating.She recently admitted: "His work ethic and his professionalism ... I have never seen a man work so hard."He was up, at 3am working out, then going to set, being a lead/main character, doing so much output. I was like, 'When do you have time for yourself?' He's really like a Superman."