The Pirates of the Caribbean actor, who shot to fame in U.K. TV comedy The Office in 2001, reveals a recent scan showed he has five slipped discs - and he has blamed his poor posture on his star status.
He tells Britain's Daily Mail, "People are only ever nice to me, but I just kind of curl up a bit. When people come up to me in the street I never know whether I have met them before and should stop and talk or just say 'Hi' and scuttle on. I tend to look at the ground to avoid eye contact; it avoids embarrassment all round.
"My back started really hurting when I went to America so I went for a scan and it turned out I had five slipped discs. They reckoned the injury was 10 years old; there was nothing that I could think of that would hurt me like that. But it is 10 years since The Office started; 10 years of walking around with my back hunched.
"In New York no one recognised me so I stood upright with really good posture. But as soon as I came home I was doubling over again."