John Simm has admitted he got into a panic about doing an American accent for his new TV show.

The Life On Mars actor stars in gritty paranormal series Intruders alongside Mira Sorvino, playing former LA cop Jack, and confessed he was so terrified the first time he had to put on an American twang that he started sweating.

"The most nerves I had were at the [script] read-through. I was terrified. I've never been nervous for a read-through, well, maybe when I was 22, for Heartbeat or Cracker," he said.

"It was the first time I'd ever done an American accent in front of anyone; not even my wife [actress Kate Magowan] had heard it. I'd just sort of done it myself, and so the first time I opened my mouth I was being recorded, sat next to Mira Sorvino. I was sweating, it was terrifying."

John, 44, went on: "You automatically think you can do an American accent because you've grown up with it - I was running around being Starsky And Hutch [as a kid]. Still am!

"The guy that helped me with the accent, I got about two lines into it and he said, 'Let me stop you there'. So it's trickier than you think it's going to be, but I loved doing it."

In Intruders, Jack's world begins to unravel when his wife Amy (Mira) goes missing and a high school friend also turns up on his doorstep looking for help with a murder case.

"Nothing is as it seems in the show, nobody is as they seem," said John.

He continued: "The thing I like about Intruders is that you don't have any answers for a while. Three episodes in, you're still thinking, 'What is going on?', but it draws you in and you want to find out.

"It rewards patience and treats the audience as intelligent; there's no signposting. It's a really intelligently-made thriller, and that's what I loved about it."

:: Intruders begins on BBC Two on Monday, October 27.