LOS ANGELES - Gary Oldman says ‘Tinker Tailor Soldier Spy’ almost gave him a nervous breakdown.

The 60-year-old actor took on the role of career intelligence officer George Smiley in the 2011 remake, a role originally taken on by Sir Alec Guinness, and he admitted that preparation for the movie took a toll on his mental health.

Speaking during a masterclass with ‘Darkest Hour’ producer Douglas Urbanski, Gary said: ‘’I had let it get to a point where it was going to crush me. It almost gave me a bloody nervous breakdown, I was so caught up in the fear of this.’’ However, his fears were eradicated when he started filming.

He said: ‘’I did the first scene, and once I had opened my mouth and started doing it, I said to myself, ‘I know where I am. I’m on a set and I’m acting’.’’

Gary also revealed that he believes self-doubt is important for actors.

He said: ‘’I think it will be a sad day to be able to watch yourself and say, ‘I think I’m fantastic in this’. Having doubt and insecurity is a good thing, but you can’t let it paralyse you.’’

While Gary won an Oscar for ‘Darkest Hour’ this year, he admitted that not all roles are as powerful and he has many reasons for taking parts.

He said: ‘’Churchill was going to take every molecule of my being to pull off. But you look for other stimulus. You’ve got to work, you’ve got to send the kids to college, you have bills to pay, you’ve got all those responsibilities. You can’t always sit around and wait for that great role to come along. You’ve got to work and you’re not always going to be hitting home runs.’’