Martin Compston "panics" about covering up his Scottish accent.
The ‘Line of Duty’ actor plays Londoner DS Steve Arnottin the BBC One police drama, and he admitted fans can be quite critical if he ever slips back into his usual manner of speaking.
He told The Sun newspaper’s Bizarre TV column: "I panic. That’s what I’m worried about with the show.
"I know my accent’s good in it, but there’s times it will go and the bigger it’s getting the more people will become accent detectives.
"So one guy will go, ‘Episode five, minute 32 – it went’ and that’s what people are like. I beat myself up a lot, I’m very critical of myself – I can watch myself back once and then that’s it."
Meanwhile, last month Martin was left "very shaken" after a horror crash when a truck smashed into the side of a taxi he was travelling in.
The 34-year-old star was on his way to a hotel in Manchester when the accident occurred and cab driver Derek Burton, 71, admitted he thought a bomb had gone off as the bang from the crash was so loud.
He said recently said: "There was a thundering bang. I thought it was a bomb. Martin screamed . We didn’t know what happened. We hadn’t seen the truck.
"It smashed into where he was sitting. Martin’s door was bashed in. It was probably doing 10mph but was so big it destroyed the cab."
Martin got into another vehicle to complete his trip but gave Derek his number in case he needed him for anything.
Derek added: "He gave me his number in case I needed him for anything. Thoroughly decent bloke."
Martin Compson panics about Line of Duty accent
