Hermione Norris has admitted becoming a mother has changed her as an actress.

The star of Spooks and Cold Feet is mother to Wilf, eight, and Hero, five, with her husband Simon Wheeler, who was a writer on Wire In The Blood, in which she also starred.

Hermione said: "Being a mother changes you more than anything else and that impacts everything you're playing because it alters you, and you understand the love a mother has for their child.

"I totally understood Rosie's reaction to the inkling that maybe her son was involved and trying to look for anything that would make that not true, from factual denial to emotional denial. That made total sense to me."

In A Mother's Son, a new two-part ITV1 drama she plays Rosie, a woman who has recently moved in with her partner Ben (played by Martin Clunes) and their respective two children from previous relationships.

As the family try to adapt to their unusual new set-up, Rosie begins to have serious suspicions that her son Jamie (played by Skins and Lead Balloon actor Alexander Arnold) was somehow involved in the murder of a local schoolgirl.

Hermione said: "I feel it raises a lot of questions on many levels about modern family life and about how a crisis like that can impact on everybody's lives."

It's a dark drama, and the 46-year-old actress admits she had to get herself into "that place" while she was filming.

"It's not the kind of place you can be in for a long time, but I knew when I took the part that if I was going to go there I may as well really go there, and I knew it was only for a short period of time so I just went for it," she explained.

:: A Mother's Son begins on ITV1 on Monday, September 3