Jessica Chastain's 'Zero Dark Thirty' character is always the ''smartest person in the room''.

The 31-year-old star plays feisty CIA agent Maya in the new movie about the death of Osama Bin Laden and Jessica admitted she was drawn to the character's intelligence.

She told People magazine: ''I thought, 'She's the smartest person in the room and she's probably always been the smartest person in the room. When you're like that you don't really make friends very easily.''

Jessica recently admitted working on the movie was ''very intense'' and she struggled with some of the dialogue.

She said: ''It was a very intense role and a lot of responsibility. It creates a conversation based on a current event; a dialogue about the time we're living in. It wasn't tense between [any of the actors], but we definitely had some tension in that there was a lot of guerrilla-style film making.

''The dialogue was very difficult. There's a lot of Arabic names, a lot of CIA jargon and facts.''