Simon Pegg says his battle with alcoholism was a ''private hell''.

The 'Lost Transmissions' star has revealed he struggled with an addiction to alcohol after using booze to self-medicate in the late 2000s, and has said that hiding his battle from his loved ones left him with a ''strange kind of split personality'', as he was trying to pretend he wasn't ''unwell''.

He said: ''I think Nick knew, but he didn't want to admit it because it was too scary. But it's a very private hell that you're in. You're trying to look OK to other people. You're creating this reality that you're not unwell, and you're trying to believe that, whereas really you're clearly not well and you're very sad, and drinking, or whatever you're doing, to try and change how you feel. It's a strange kind of split personality that you have.''

Simon, 50, eventually checked into rehab to help him get sober, and has credited 'Mission: Impossible -- Ghost Protocol' - the first film he starred in after leaving the treatment centre - with helping him get back on his feet.

He added: ''They were really helpful. They made sure that my family was on standby to come out if needs be. One of the problems you have as an actor sometimes is separation anxiety. You're away from your family a lot. I'd just had a baby and the thought of being away for a long time was troubling me, so they were just really helpful in making sure I was feeling happy and comfortable.

''By that time I was in a much, much better place. That film couldn't have come at a better time because I got in good shape and started to just have fun, working with Brad [Bird, director] and Tom [Cruise]. It was an adventure. We went to Prague and Dubai and Vancouver. It was part of my recovery, I think.''

And Simon says co-star Tom Cruise was always ''very supportive'' of him.

When asked if Tom knew about his trip to rehab, Simon told The Sunday Times' Culture magazine: ''Yeah. I didn't ask who knew, but I think he did. He's always been very supportive.''