Michael Fassbender passed out filming a violent sex scene in 12 Years a Slave.
The 36-year-old actor - who plays nefarious slave owner Epps in the slavery drama - found shooting the sexual assault scene with co-star Lupita Nyong'o so harrowing he temporarily "blacked out."
He said: "That's never happened to me before. I don't know what happened. Maybe I hyperventilated? But I blacked out and I came to and I was on top of Lupita thinking, 'What the f**k?' Then I saw the camera and the lights and I was like, 'Oh yeah, we're filming.' "
Despite the troubling nature of the film, which also includes scenes of torture, Fassbender insists the cast and crew tried to remain upbeat and not get too consumed by the dark subject matter.
He added: "That's always the way. I think it's a defense mechanism to not allow the atmosphere to get too steeped. At lunchtime, we sat down together and tried to switch off because the moments when we were on were so intense."