Ryan Reynolds remembers "connecting" with something "tall, dark and expensive" before giving Denzel Washington a black eye.

The actor stars alongside Denzel in the upcoming action thriller Safe House. The movie follows a young house-sitter who, after a bunch of rebels destroy a CIA-operated safe house, must move a criminal to another secure location. Ryan plays sitter Matt Weston, who is in conflict with notorious criminal Tobin Frost, portrayed by Denzel.

Shooting the high-octane movie didn't come without its perils. In one violent car scene, Ryan ended up giving Denzel a black eye.

"We're having a pretty intense fight scene in the car and we're all over the place," he recalled in an interview with BBC Breakfast.

"And I felt my head connect with something tall dark and expensive. It was pretty awful."

When asked if the blow was intentional, the star jokingly added: "Nobody likes a backseat driver!"

Ryan was thrilled to work alongside Hollywood legend Denzel. The 35-year-old star made sure he was prepared before stepping out on set with the actor.

"I'd met him once before at an event a few years earlier. You definitely want to know your stuff when you come in. I think for any actor, young or old, you'd be excited to work with him," he smiled.

"He's like a living, breathing masterclass in acting."

Ryan is proud of the action picture. He has joked that audiences can lose up to "10 lbs" watching it.

"You do a lot of training to make sure no huge celebrities get black eyes, but obviously that doesn't help," he quipped.

"It takes three days to do a five minute fight sequence so by that point you're pretty much black and blue."