28 Years Later actor recorded audition with his nan

A 24-year-old Welsh actor says he recorded a self tape with his nan to land a role in a highly-anticipated post-apocalyptic horror film.

Director Danny Boyle's new film 28 Years Later - the third in the series that began with 28 Days Later back in 2002 - was released in UK cinemas on Thursday.

The new chapter of the story, starring Jodie Comer, Aaron Taylor-Johnson and Ralph Fiennes, features 24-year-old Sam Locke from Merthyr Tydfil, making his feature film debut.

But Locke said his casting journey for the project had humble beginnings in Wales.

He said he was visiting his grandmother, Wendy, when the call came in for the self-tape.

"We had a good time filming that, she read in for the roles," he told Behnaz Akhgar on BBC Radio Wales.

He added he was back with his nan, "in the same living room", when he got the good news that he had secured the job, nearly three months later.

"I was sat with my grandfather and he was telling me 'if you don't get the role, don't be disheartened' and literally about 10 minutes after my agent rang with the confirmation," he said.

"There was a lot of excitement."

He said he would be watching the film on release day with his mother and some family friends, but would be sure to take his grandparents for a trip to the cinema soon.

He said he was proud of everything he had achieved, but equally of his Merthyr roots.

"I pinch myself every day."

28 Years Later picks the story up as survivors find a way to exist among the infected after the Rage virus escaped a medical research laboratory.

It is set on Holy Island, or Lindisfarne, a real-life island off the coast of north-east England.

"That's where the survivors of our story live and then it takes us onto the mainland many times, and you see what's lying over there," said Locke.

He warned this film, like those that came before it in the trilogy, was "very gory", adding he did not want to give too much away, but could reveal he plays a "minimal" role in this film - but one which helps set the plot up "for films going forward".

"We're very energetic, we're very physical, and it's a conversation starter," he said.

"Luckily I'm quite active anyway," added the keen skateboarder and Liverpool FC fan.

"But we had a week of stunt training and that pretty much trained our endurance.

"It helped us gel together, my immediate cast. We needed that week, and you'll see why."

He said he loved working with "film-making royalty" Danny Boyle, adding: "It's bucket list, for almost any actor, so when I found out I got it I did more research on him and was excited to work with him."

But being on set, he said, was "a different kettle of fish".

"He's got authority, but he's calm with it. He makes you feel comfortable," he said.

Locke said the premier in London on Wednesday, which was the first viewing of the finished film for him and some of the other supporting cast members, was "brilliant".

"We were all blown away," he said.

Locke previously starred in the BBC series The Way - directed by Michael Sheen - while he was still a student.

"To be part of that, with so much Welsh talent… Michael Sheen's passion towards the project rubbed off on everyone involved."