Joaquin Phoenix worries about becoming addicted to winning awards.

The 43-year-old actor is currently being praised for his role as the damaged ex-soldier Joe in 'If You Were Never Really Here' and he won the coveted Best Actor gong at the Cannes Film Festival, but admitted he is ''terrified'' of award season.

He told the Metro newspaper: ''There's a part of me that fears if you appreciate or enjoy that too much, it means you're getting soft and old and you'll stop fighting. And I'm terrified of it.

''I guess the fear is that it will be addictive and you'll start pandering, right?

''For me, thus far, I've managed to stave that off and to feel like working on a movie is always the greatest reward.

''The process is something I really enjoy. I guess I'm always scared that it will change the way you approach things.''

When the actor won the award, he was ''totally f**king shocked'' and didn't anticipate winning, and accepted it wearing his Converse boots.

He said: ''I was totally f**king shocked, I didn't anticipate it at all.''

The film follows Joe who is hired to rescue a sex-trafficked daughter of a senator but the mission goes seriously wrong.

For the part, Phoenix got himself a personal trainer to pump him up but admitted the physical effects started to change him.

He said: ''It's fun at first and then it's weird. It starts to change you... the physical affects the emotional or the mental.

''You feel differently about yourself. It's interesting to feel your body in that way.

''I think that was the biggest I'd been for a while. At first it's great and then it's like, 'f**k!' You have to go in on weekends to try and maintain it.''