Michael Gambon joins the cast of ITV's Fearless

Fearless follows McCrory’s dedicated solicitor Emma Banville as she works tirelessly to free a man she thinks was wrongly convicted of killing a schoolgirl in East Anglia.

However, as her investigation digs deeper, she begins to sense powerful forces, in the police and the intelligence services at home and abroad, who want to stop her uncovering the truth.

Executive Producer Damien Timmer said of the casting: "Michael Gambon is a legend, one of the UK's finest actors, and it's a real thrill for us that he will be joining the brilliant Helen McCrory in Fearless.

“The range and depth of the cast that director Pete Travis has assembled is testament to Patrick Harbinson's wonderful scripts, following Emma Banville as she risks everything in her quest for the truth."

The six-part series also stars comedian John Bishop, Emmy nominee Robin Weigert (Jessica Jones), Jonathan Forbes (Catastrophe), Wunmi Mosaku (Dancing on the Edge) and Marcella’s Jamie Bamber.

Christine Bottomley (In the Club), Rebecca Collard (Ordinary Lives), Emma Hamilton (Mr Selfridge), Kika Markham (Secret State), Jack Shepherd (The Politician's Husband), Sam Swainsbury (Mum) and Happy Valley's Rick Warden will also appear.

Fearless is produced by Mammoth Screen, the same team behind ITV’s regal drama Victoria, hit BBC1 drama Poldark and Endeavour.

Fearless comes to ITV in 2017