Next month, Jude Law returns to our screens in Black Sea, which see the actor star as submarine captain Robinson, who leads his crew on a quest to find a treasure-filled Nazi vessel lost at the bottom of the ocean. But in order to prepare for the challenging role of a submarine captain, the actor actually spent time with the Royal Navy, taking part on a two day mission.

Jude LawLaw stars as a submarine captain in Black Sea

Speaking to Esquire, the actor said he, “was very lucky to be invited by the Royal Navy to go off on a submarine mission, so I went off for a couple of days with them. To be honest, more for a life experience than any sort of research.”

"We shot the film on an actual submarine that some wonderful, crazy guy had bought and had sitting in an estuary in (English town) Rochester. Being there, rather than on a set, heightened the drama for us. You're on top of each other and it gets very claustrophobic,” he added.

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However despite a tight squeeze onboard, the cast (which includes Scoot McNairy and Karl Davies) got on just fine. “There was a lot of humour,” Law said.

The film also sees Law try his hand at a Scottish accent, something which was his and director Kevin MacDonald’s idea. “We were trying to create a backstory that had a grittiness, a dignity to it,” said Law.

“I also wanted to hint at a past for Robinson where he grew up beside the sea, or perhaps you could imagine his father also being laid off or let down by the government. Anyway, because Kevin’s Scottish it felt like a safer choice than going Irish,” the actor concluded.

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Next for Law is a role in Paul Feig directed comedy Spy, alongside Melissa McCarthy. He’s also currently filming Genius, a true story set in 1920s New York, directed by Michael Grandage.

Black Sea is released in the UK on December 14th and in the U.S. on January 15th.