Dublin actor Andrew Scott is to star in the film adaptation of Arthur Ransome's best-selling children's adventure Swallows and Amazons.
First published in 1930, Swallows and Amazons follows the outdoor adventures of two families of children, the Walkers and the Blacketts, and their battle of wits against the Turners' enigmatic uncle Jim (Rafe Spall), aka Captain Flint.
Scott will play a secret agent, Lazlow, who is on the trail of Jim Turner.
The cast also includes Kelly Macdonald and Harry Enfield, and Philippa Lowthorpe, whose credits include Call the Midwife, Jamaica Inn and The Other Boleyn Girl, is directing.
The film is currently in production in the English Lake District.
Speaking to Variety, Scott said one of the reasons that he was drawn to the character of Lazlow was the fact that he was so different to his best-known role, as the villain Moriarty in the BBC's Sherlock.
"He's a very charismatic character, and there is humour and warmth in the character," he said. "It's a great part; it's very witty. It's a very attractive character to play, so I'm delighted to be on board."
He added: "The chief reason I'm on board is because I love the storyline. That's the thing that attracts me to any project - a great script and a really good story."
Scott will soon be seen on cinema screens in the new James Bond adventure Spectre. It opens on November 6.