Irish actor Colin Farrell has said the pressure of making his latest release 'Phone Booth' drove him to drink.

The 27-year-old Dubliner stars as a New York publicist trapped in a phone booth by a sniper, who is on the other end of the line.

The film, which was shot in just 12 days, focuses almost completely on the actor in the phone booth.

He told reporters, "I went out on the lash - and I had a load of drinks because I had to unwind. My head was destroyed… I nearly wanted to cry at the end of the day. It sounds so stupid saying it, you know? But it was a tough enough gig."

The release of 'Phone Booth' was postponed after last year's real-life US sniper attacks.

Now out in the US, it hits screens across Ireland on 18 April.