Greenock-born Compston, who does a fine London accent in his role as Detective Inspector Steve Arnott, admits he just wasn't any good at a Brummie accent.
Speaking on the latest episode of The Restless Natives podcast, which he co-hosts with Gordon Smart, the 38-year-old revealed: “I genuinely couldn’t just put on a Brummie accent now, I’m not good at accents. I actually went up for Peaky Blinders.
“I went for Tommy Shelby, thought I nailed the f***** thing and Jed Mercurio who writes Line of Duty, he’s a Brummie so he recorded my lines for me and it was one of those moments where I was like, ‘I’ve got a shout’ and then my agent goes 'Cillian Murphy’s going for it.' So you just know you don’t ever follow up again ever.”
Earlier this week, it was reported that Amazon Prime’s new Edinburgh-filmed thriller, which stars Compston, had stormed to the top of the streaming giant's charts in both the UK and the US amid critical acclaim.
The Rig, most of which was shot at FirstStage Studios at Bath Road in Leith, was the most-watched show in the UK over the weekend, as well Amazon Prime's top show in America, Germany and a host of other countries.
The six-part series, which also stars Game of Thrones’ actor Iain Glen, tells the story of a North Sea oil rig off the Scottish coast which gets cut off from all communication with the shore and the outside world due to earth tremors.
“As the crew endeavour to discover what’s driving this unknown force, a major accident forces them to ask questions about who they can really trust,” according to a statement from the programme makers.
The crew “will be driven to the limits of both their loyalties and their endurance, into a confrontation with forces beyond their imagination”, it added.
The series was created by David Macpherson and is directed by John Strickland.
The Rig, which had its premiere at the Everyman Cinema in St James Quarter in December, also stars Schitt’s Creek star Emily Hampshire and Small Axe’s Rochenda Sandall.
Owen Teale, Richard Pepple, Mark Bonnar, Calvin Demba, Emun Elliott, Abraham Popoola, Stuart McQuarrie and Molly Vevers also appear in the series.
As he took to the red carpet in the Capital last month, Compston, whose father worked on a Scottish oil rig, said: “I love Edinburgh and I think more shows will be coming to film here, especially as the studios in Leith where we filmed are just amazing.”
The Scottish actor described his character in the show as “a good wee guy”.
When comparing his character in Line of Duty (Steve Arnott) to that of Fulmer in The Rig, he said: “Steve was more of a lost wee soul, whereas Fulmer is more of a pitbull.”