Colin Firth reveals initial 'Tinker, Tailor, Soldier, Spy' concerns

Colin Firth has confessed that he had "initial" worries over Tinker, Tailor, Soldier, Spy.

The Oscar-winning actor admitted that he held concerns over whether his role as Bill Haydon in the Tomas Alfredson thriller may have been too challenging.

The King's Speech star told PA: "There's an initial moment when you walk on the set and think, 'Oh, I might be out of my league'."

However, he added: "I don't think any actor is so selfless to only luxuriate in ensemble work, but I was absolutely up for it."

Tinker, Tailor, Soldier, Spy, which also stars Benedict Cumberbatch, currently sits atop the UK box office chart.

Watch a trailer for Tinker, Tailor, Soldier, Spy below: