Liam Neeson's sex scene with Judy Davis in Husbands & Wives was made extra awkward after director Woody Allen discovered his then-wife Mia Farrow had realised he was romancing her adopted daughter.

Neeson tells GQ magazine he was preparing for his lovemaking scene when Allen learned Farrow had found naked photographs he had taken of Soon-Yi Previn, who is now his wife.

The actor admits he knew something was wrong when the usually punctual Allen showed up on set 20 minutes late.

He recalls, "There's a scene where I'm going down on Judy Davis, right. Judy and I are in bed, obviously covered up, and as I'm going down, Judy's having this monologue in her head. And the crew are all ready, and we're waiting for Woody. No-show.

"It's starting to get a bit uncomfortable, it's a bed scene. Anyway, he came out after about 20 minutes and said, 'Ok! (The) camera starts on Judy. Liam, I want to just see the top of your head. Ok, we know where you're going...' There was no apology; nothing."