Grace returns to our screens tonight (April 6) with four thrilling new cases that are sure to captivate audiences.

In the latest episode titled Dead If You Don't, Roy Grace, portrayed by John Simm, finds his day off at a football match turning into chaos.

John Simm, who leads the cast of the ITV drama, has shared details about a particularly intense moment during filming involving a complex stunt for the highly-anticipated season five premiere.

The nail-biting scene required Simm's character to dive under a pier to rescue someone from the dangers of a swiftly rising tide.

Chatting with media including Express.co.uk, the 54 year old actor recounted: "That was a very challenging day, I have to say."

He humorously remarked: "I have PTSD after that."

The star of Life on Mars further described the experience: "It was cold. Yeah, it was full-on, it was a long day."

Simm gave insights into the technical aspects of filming the dramatic scene and noted how the fiction of the storyline was closely aligned with the actual conditions on set.

He detailed the intense scenario: "We were under the pier and it was filling up with water as well, so there's really no acting required. I'm swimming in a suit, trying to untie a guy that's tied up and get him through the water, hold his head up above the water and try to get him out."