Nick Frost "put his back out" while filming a dance-off with Chris O'Dowd for their new romantic comedy 'Cuban Fury.'
Speaking at the UK premiere of the film at the Vue Cinema in London's Leicester Square last night, director James Griffiths said: "Nick injured himself very badly actually during the rooftop dance. We had to go back and film some elements.
"We had some wires when he catches Chris O'Dowd and I remember it, he sort of throws Chris down in the air and catches him and Nick, in true style, very gritty, caught him for real. He put his back out.
"So the next day was a bit of a panic. He had a lot of massages and a lot of oils. I think he quite enjoyed it."
Nick, 41, who conceived the film, and O'Dowd attended the premiere alongside their co-stars Rashida Jones, Olivia Colman and Kayvan Novak, as well as singer Paloma Faith.
Other stars on the red carpet included Lake Bell and Simon Pegg, who are currently filming the movie 'Man Up' together in London.
The film hits cinemas in the UK on February 14.