A tense biographical thriller movie is airing on TV tonight

The film holds an 89% Rotten Tomatoes score.

In the film, the Black Doves actress plays real-life British woman Katharine Gun who worked as a translator for the Government Communications Headquarters (GCHQ) before becoming an Iraq War whistleblower.

The plot synopsis for the movie reads:

"One day in 2003, in the lead up to the Iraq War, British intelligence specialist Katharine Gun receives a memo from the NSA with a shocking directive: the United States is enlisting Britain's help in collecting compromising information on U.N. Security Council members to blackmail them into voting in favor of an invasion of Iraq.

"Unable to stand by and watch the world be rushed into war, Gun makes the gut-wrenching decision to defy her government and leak the memo to the press."

Directed by Gavin Hood (Eye in the Sky, Wolverine), the starry cast of Official Secrets also includes Conleth Hill, Indira Varma, Jeremy Northam, Matt Smith, Matthew Goode, MyAnna Buring, Ralph Fiennes, Rhys Ifans and Tamsin Greig.

The film earned very positive notices upon release, with particular praise being given to Knightley for her central turn and the movie's important story.

It garnered an 82% critics score and an 89% audience score on Rotten Tomatoes.

Official Secrets is airing on TV tonight on BBC Two at 11pm.

Here are the other movies airing on TV tonight:

Cardboard Gangsters - TG4 - 9.30pm

A gang of lads selling drugs in Darndale in Dublin's Northside sets out to gain more money and power and enter the big leagues of the narcotics trade.

Harry Potter and the Half-Blood Prince - ITV2 - 8.10pm

The sixth installment of the iconic fantasy adventure franchise, starring Daniel Radcliffe, Michael Gambon, Emma Watson, Rupert Grint, Tom Felton and Alan Rickman.

Runaway Jury - Legend Xtra - 9pm

A woman sets in motion a multimillion-dollar lawsuit against the manufacturer of the gun that was used to kill her husband - but her actions spark an unexpected series of events.

Taken 2 - ITV4 - 11.10pm

Action thriller sequel, starring Liam Neeson, Maggie Grace and Famke Janssen.

Thick as Thieves - Legend Xtra - 11.05pm

An experienced criminal finds himself heavily in debt to Russian mobsters after his former partner co-operated with the police.