The first pictures have been released of Line of Duty star Martin Compston’s guest turn in Scottish sitcom Still Game.

In the episode, airing on the new BBC Scotland channel on Sunday, Jack and Victor are trying to buy mobile phones and head to a shop where Compston’s character works.

Compston was filming the fifth series of BBC crime drama Line of Duty in Belfast but was able to return to his native Scotland for his appearance.

He said: “It was surreal standing across from the two of them as Jack and Victor. I know the boys as Ford and Greg but when they put on the make-up and start becoming the characters it really is a very surreal moment.

“Luckily I was filming Line of Duty at the same time, so I was able to pop over from Belfast and shoot my scenes.

“It was an epic day. To see the boys do their thing was immense.”

Martin Compston with Gianni CapaldiMartin Compston with Gianni Capaldi, left, in Still Game (Alan Peebles/BBC/PA)

The episode marks the start of the ninth and final series of the show, which returned in 2016 after a nine-year hiatus.

Singer-songwriters Midge Ure and Amy MacDonald are also among guest stars announced to turn up during the final run.

Compston described the show as “an institution” and “one of the best Scottish TV shows of all time”.

He added: “I spend a lot of time on the road and I’m always sticking it on to watch as it reminds me of home.

“It’s a show you can watch with your mum, dad and whenever I was away on bus trips with the football teams, we’d put it on and watch for hours and everybody would be happy.

“Anytime I feel a wee bit homesick in Las Vegas I stick Still Game on.”

The show’s creators and main stars Greg Hemphill and Ford Kiernan both describe the final episode as their favourite from the upcoming series.

Kiernan said: “You’ve grown to know all these characters over the years and what we’ve tried to do is put a resolve on all of them.

“My memory will be us all bolstering ourselves to get through the final scenes, knowing that we’ve done the right thing.

Still GameStill Game stars Greg Hemphill and Ford Kiernan say the show will not return again (Alan Peebles/BBC Scotland)

“I think the longevity and the length of time people have been prepared to stick with us and keep supporting us.

“I’m delighted with the way it’s worked out and just how good they are to us.”

Hemphill added: “It feels bittersweet, very strange.

“(Audiences) can expect a lot of stories – not just Jack and Victor’s – to end because it’s the finale and the last chance the audience will get to see them on the TV. It’s important everybody’s stories are tied up.

“We had Martin Compston in the first episode which was good fun. He’d expressed a love of the show and is a big fan of Still Game.

“He’s one of the biggest stars in the UK at the moment, so for him to come in and spend a bit of time with us was fun.”

Compston, who recently starred in Mary Queen of Scots on the big screen, also said he was “gutted” about Still Game’s end.

He added: “It’s the same with all good things – it’s better you go out on a high. It’s better the boys taking the decision to end it rather than it being forced upon them. This way, they can actually write an ending.

“I know the boys are saying it’s done but the fact that they’re playing old guys, 20, 30, 40 years older than them means that there’s so much scope for them in the future. But that depends on the ending.

“They could literally bring this show back in 30 years time – just using less make-up.”