Colin Farrell was terrified of sober sex.

The 'Winter's Tale' star - who has been clean for eight years - admitted he initially struggled to get used to making love without alcohol and was scared by the change.

Speaking to ELLE magazine, he said: ''I worried I wouldn't be able to talk, full stop. I hadn't uttered a word sober in about 15 years ... I made love to a woman about two and a half years after I got clean, and it was one of the most terrifying moments of my life.

''It was in the afternoon. The windows and the curtains were open. It was lovely, and, to be crass, it wasn't f**king.

''She was very gentle. But it was terrifying. Because I was just used to drunkenness and dark rooms and clubs and toilets and wherever.''

The 37-year-old actor also discussed a fling which led to the filming of a sex tape - which he blocked from release via an injunction - and admitted he is worried his mother could accidentally stumble on it.

He added: ''It certainly wasn't a validation of my prowess. The whole thing was horrifying. You know, Press Record. Taboo.

''Isn't this interesting? I was deposed for four hours explaining why I didn't want it to be released.

''God forbid it's an On Demand movie in a hotel room and my mother says, 'Oh, I haven't seen this work of my son's', and hits purchase.''