ACTOR Matthew Lewis joins the new series of hit drama Happy Valley, starting tomorrow.

The highly anticipated second series of Sally Wainwright’s multi Bafta-winning series is filmed in Calderdale, with a mortuary scene also shot in Bradford.

Sarah Lancashire plays Catherine Cawood, a forthright police sergeant back heading up her team in the Calder Valley following the jailing of Tommy Lee Royce, who raped her daughter.

When Catherine discovers a decomposed body in a garage she soon finds herself in the midst of a murder investigation, with shocking repercussions for her and her family.

Matthew, of Horsforth, who shot to fame as a child actor playing Neville Longbottom in the Harry Potter movies, appears in Happy Valley as Sean Balmforth.

"I knew it'd be a challenge, probably my biggest to date, but I was eager to be involved and to work with Sally Wainwright," he said.

"Sean had a bad start in life, it's defined him in ways that are out of his control. He's angry and lost and finds it difficult to express his emotions which, coupled with his drinking, can become a tinderbox.

"I can't say too much without giving away parts of the story, but he's in a very dark place. Getting into the mind of somebody with those problems and thought processes was daunting. Luckily I had a superb cast and crew around to help out."

Happy Valley has won more than 30 awards, including Baftas for Best Drama Series and Best Writer.

The cast also includes Siobhan Finneran, Amelia Bullmore, George Costigan and former Coronation Street stars Julie Hesmondhalgh and Catherine Kelly.

"Roughly 20 years ago I had a part in Where The Heart Is, which Sarah was the lead in. I was about six and my mother was played by Siobhan," said Matthew.

"Getting back together with those two after so many years was incredible.

"There was a wonderful moment off-set when Sarah and Siobhan were talking about a big scene they had coming up.

"Sarah half knew it and Siobhan hadn't really looked at it. They decided to run it together, it was a big scene, about ten pages, and after about four pages Siobhan had got as far as she'd prepared.

"Sarah kept going so Siobhan basically guessed what her character would say and it just fitted, every single time, Sarah had a cue and was able to keep going with her dialogue.

"They inhabit their characters so well and work off each other like real sisters. It was a pleasure to watch. I wasn't there for the actual shooting of the scene a few days later but I bet it was a corker."

Matthew's other TV credits include Kay Mellor's The Syndicate and Bluestone 42. In 2012 he was awarded an honorary doctorate from the University of Bradford. He appears in a new film, Me Before You, released this year, and the next season of BBC1 drama Ripper Street, currently filming.

"I'm growing my 19th century sideburns and moustache back as we speak," he said.

* Happy Valley returns to BBC1 tomorrow at 9pm.