Gerard Butler has admitted he "almost killed" Hilary Swank while filming the 2007 tearjerker P.S. I Love You.
During an appearance on Tuesday's episode of The Drew Barrymore Show to promote his action-thriller Plane, the actor revealed Hilary got injured while they were filming a scene from the romance drama.
In the scene, his character, Gerry Kennedy, danced "like an idiot" in boxer shorts and suspenders.
The plan was for him to get hit in the face with a suspender clip while undressing, but the metal fastener ended up slicing his co-star's head instead.
"It (got) stuck, it release(d) and (flew) over my head," the 53-year-old actor explained of the suspender clip. "Hits her in the head. Slashes her head. I cut her open. You could even see the teeth (of the clip). She had to get taken to the hospital."
The Scottish actor recalled that the studio emptied out "in three seconds" and he was left there crying in his costume.
He added, "I scarred Hilary Swank. I almost took her eye out, and I just made a fool of myself for two days and this is all I have to show for it."
Gerard explained the metal fasteners were so dangerous that the film crew had to wear plastic shields to protect themselves from the flying metal.
While he felt terrible for the accident, he said Hilary, 48, was a "great" person to work with.
In P.S. I Love You, Gerard portrays a man who has recently passed away and has left a series of letters for his widow, played by Hilary, to help guide her through her grief.
The film, directed by Richard LaGravenese, was released in December 2007 and was a commercial success, earning a worldwide gross of $156.8 million (£126.4 million) on a $30 million (£24 million) budget.