Suranne Jones was kept apart from co-star Jason Watkins in rehearsals for new play Frozen

Suranne Jones revealed she was kept apart from co-star Jason Watkins for most of the rehearsals for Frozen, to make the moment of their meeting on stage more “powerful”.

The actress plays Nancy — the mother of a murdered daughter — with Watkins as the serial sex attacker who killed her.

Director Jonathan Munby said the cast “pretty much” rehearsed separately.

“The first part of rehearsals we were together, when we were doing the research, but as soon as I could I separated them,” he said.

“I knew at one point these characters collide and that moment was going to be very, very powerful for these actors who don’t really know each other.”

Buy tickets for Frozen with GO London

In the play by Bryony Lavery, Jones’s character confronts her daughter’s murderer in prison after his trial, said: “What is really powerful is we don’t speak to each other for over a minute and when we very first rehearsed it, that came,” she said.

“We were just looking at each other and it was a really important moment because I’m looking at a man and the last moments of my child, and he’s looking at an older face of the child he killed.

“I think it’s a really brave choice of Jonathan’s to have us in silence, but we’ve earned it because I’ve just been talking to the audience and I haven’t had scenes with other actors.”

The Doctor Foster actress, 39, was back on stage for the first time in almost four years. She said her return to theatre had been delayed by the success of the BBC show and the arrival of her first child with husband Laurence Akers.

“I knew I wanted to do theatre and I’d read about 20 plays. But I wasn’t sure what I wanted to do and then I read this play,” she said. “It affected me in a way that I knew I needed to do it, even though it was going to be a lot of hard work and a really tough subject.”

Jones, who discussed the story with a criminologist and met parents of missing children as part of her research, said the plot was “every mother’s nightmare”.

She said: “My character goes through a journey of forgiveness and I think that became the main topic. Can you forgive? And what does that do to a person? And actually it frees you.”