Louis Ashbourne Serkis, front, get a hug from Patrick Stewart in a scene from “The Kid Who Would Be King.” Louis, 14, is the star of the new movie, which is a twist on the legend of King Arthur. (Kerry Brown/20th Century Fox via AP)

Acting is an inherited trait for 14-year-old Louis (pronounced “LU-ee”) Ashbourne Serkis, the star of the modern-day Arthurian-legend adventure “The Kid Who Would Be King.”

Not only is Louis’s father, Andy Serkis, an award-winning actor (Klaue in “Black Panther,” Gollum in “The Lord of the Rings” trilogy and Snoke in “The Last Jedi”), but his mother, aunt and older siblings act as well.

“I grew up on film sets, like as a baby on ‘King Kong,’ ” the actor told KidsPost. “I started to realize when I was 6 or 7 that it would be quite cool to entertain people for a living.”

At that point the young Londoner “just got into it,” booking auditions and early roles, the first of which was a bit part in 2015’s grown-up mystery drama “Child 44.”

Louis had to do physical training to prepare for using a sword. (Kerry Brown/20th Century Fox via AP)

“I did my first small thing when I was 7, but it was tiny,” he recalled. “I played Gary Oldman’s son, but my part got cut out of the film.”

Since that first edited-out performance, Louis has racked up nine film and television credits, a mix of live-action, animated and motion-capture work (an art form his father is famous for perfecting). But when it came to securing his leading role in “The Kid Who Would Be King,” Louis wasn’t even sure what the movie was about initially.

“I was walking home from school, and my mum rang me and said, ‘You’ve got to come home now, you have this audition,’ ” he said. “I didn’t know anything about it, and I did my first audition in my sports [uniform].”

Despite wearing his gym clothes to the first screen test, Louis scored a second audition, a one-on-one with the director Joe Cornish, for the big part. Alex is a 12-year-old schoolboy who can somehow wield the sword in the stone and must rally a group of “knights,” including two school bullies, to fight Morgana, an evil sorceress who wants to reclaim the sword — and all of Britain — for herself.

Louis explained that like most British kids, he grew up familiar with stories about King Arthur, his sword Excalibur and the Knights of the Round Table, but after earning the role, he did even more research.

“I watched ‘Excalibur,’ which Patrick was in,” Louis said about the 1987 fantasy in which his co-star Patrick Stewart plays King Arthur’s father-in-law, King Leodegrance. “And I read the Michael Morpurgo book ‘Arthur, High King of Britain,’ but also at school we’ve always heard the classic tale that whoever pulls the sword out becomes the king.”

Louis became friends with the young actors who play knights, from left, Rhianna Dorris, Tom Taylor, Dean Chaumoo. (Kerry Brown/20th Century Fox via AP)

In addition to brushing up on his Arthurian trivia, Louis had to do a “load of” physical training to prepare for using a medieval sword, wearing armor and riding horseback.

“There was like two months of solid horse-riding and sword-fighting practice and getting fit,” Louis explained. “That was really tough. The first time I tried the horse-riding lessons, it was quite hard to get used to, but it was worth it.”

Through the preproduction training and the shoot, Louis bonded with his on-screen knights (teen actors Tom Taylor, Rhianna Dorris and Dean Chaumoo), who appear in almost every major scene with him.

“We’ve become such close friends that we’re going to be mates for life,” he said. “I’m really grateful that we had this opportunity together.”

If all goes well, Louis and his co-stars could have another chance to show off their medieval sword-fighting skills.

“Hopefully there will be a sequel,” he said.

Louis attends a media event for “The Kid Who Would Be King” last week in New York. (Dia Dipasupil/Getty Images)
More about Louis

Siblings: Older sister Ruby is 20, and older brother Sonny is 18. “Both of them act as well.”

Pets: “I’ve got two cats: One of them is called Dilly, and the other one’s called Teddy.”

Education: Highgate School, a private school in London — founded in 1565! “When I’m filming, though, I have a tutor on set.”

Favorite book:The Enemy” by Charlie Higson. “It’s a teen book about zombies. There are these kids who fight a disease that turns people above a certain age into a zombie.”

Favorite movie: “My family loves to watch ‘Elf’ together.”

Favorite scene in the movie: “My favorite scene is when we’re being taught to sword fight by the trees. I found that really fun, and it was quite challenging.”

Favorite superhero: “Captain America. He was the first Avenger, he’s strong and he’s got the shield.”

Actor/actress he’d most like to work with: Mark Wahlberg. “He’s funny and seems quite nice and fun to work with. I really liked him in ‘The Fighter,’ which is a good film.”

Hobbies: “I like watching Arsenal and going to football [soccer] matches. Playing football. Seeing friends and going to cinema.”