Idris Elba didn't think Aaron Sorkin would be open to improvisation while shooting 'Molly's Game'.

Idris Elba at Molly's Game premiere

Idris Elba at Molly's Game premiere

The 45-year-old actor stars as real-life defence lawyer Charlie Jaffey - who represented poker game organiser Molly Bloom in court - in the directorial debut of Sorkin and Elba said the filmmaker was "very pragmatic" when it came to letting the cast put their own ideas and lines into the film.

Speaking to BANG Showbiz at the UK premiere of the movie at Vue Cinema in London's Leicester Square on Wednesday night (06.12.17), Elba said: "Aaron is brilliant. He is a really nice guy and was very pragmatic. He was very open to suggestions. You know, with Aaron's work you don't want to improvise, you want to say the words as they are written but you know sometimes you can't help say something a different way, which he is very good about but I didn't think he would and he was."

The film is based on Bloom's memoir 'Molly's Game: From Hollywood's Elite to Wall Street's Billionaire Boys Club, My High-Stakes Adventure in the World of Underground Poker' and follows the true story of the beautiful, young, Olympic-class skier - played by Jessica Chastain - who ran the world's most exclusive high-stakes poker game for a decade before being arrested in the middle of the night by the FBI.

Players included Hollywood royalty, sports stars, business titans and the Russian mob but her own ally in her bid to defend herself is her criminal defence lawyer Charlie.

Although he plays a real-life person in the drama, Elba insists he didn't find the experience any different to portraying any other character.

He said: "I guess, you know, any approach to any story whether true or not for an actor's point of view is to be able to, at least, own your character, own your interpretation of the character. A lot of the time the directors don't know exactly what they want to see when an actor walks in so as long as you, the actor, knows who you are and who your character is and that's enough."