At 15, Noah Schnapp has already earned more money than most of us will make in a lifetime. As one of the recurring original cast members of the hit series Stranger Things (he plays Will Byers, the imperilled son of single mother Joyce, played by Winona Ryder), he reportedly saw his salary of around £15k per episode, for seasons one and two, soar to a whopping £190k for season three. There is a fourth one on the horizon — “It’s not the final season,” he assures me— so it could climb even higher.

And why not? Last year, Netflix announced that the first episode of Stranger Things 3 had more viewers in its first four days than any film or show on the streaming service: it is the goose that keeps laying golden eggs.

Schnapp, for all his wealth, is like any other teenager, though, and just before we are set to talk about his new film, Waiting for Anya, an email arrives from a publicist saying we’ll have to delay the interview, because his schedule has “shifted due to schooling”.

Acting wasn’t always work for Schnapp. He started doing it for fun aged six, and then enrolled in an acting class. At eight, his teacher told him he should try it professionally. After a few slow years, and lots of rejection, he won his first movie role in Steven Spielberg’s Bridge of Spies. Next came voice work as Charlie Brown in The Peanuts Movie. The following year, Stranger Things debuted.

Like all of these, Waiting for Anya takes him into the past. Based on the novel by Michael Morpurgo, it is a gentle coming-of-age story set against the natural beauty of the French Pyrenees. Schnapp plays a shepherd boy called Jo, who helps a widow (Anjelica Huston) smuggle Jewish children across the border into Spain, while living under German occupation.

“They sent me the script and I was really excited about it,” he says. “I read the book and I really resonated with it, being Jewish.” Schnapp has had his bar mitzvah since making the film. “I did it in Israel,” he reveals. “It was really cool.”

Ironically, Jo isn’t Jewish. However, the story allowed Schnapp to look at the situation through the eyes of someone who makes a choice to help.

“He’s inspiring,” he enthuses. “He’s this hero who risks his life and puts others before himself. I feel like it really teaches a good lesson to people to be compassionate and not selfish . . . He’s very inspiring. I don’t know, but I hope I’d do the same amazing things he does.”

Even in the small village of Accous where they filmed, Schnapp found himself surrounded by adoring fans. According to the film’s executive producer, Victor Glynn, “French girls flocked to see him.” Schnapp says none of the Stranger Things actors “really expected how much it would blow up in attraction and the followers we would gain.”

He talks generously about the support he receives from fans, but also recognises the microscope the show has put him under at a time of life when making mistakes is natural. How “normal” a life can he lead? I ask. Does he always have to monitor his behaviour?

“For sure,” he says. “That’s definitely a part of it, that you have to be aware and always make sure you’re careful and don’t, like, do anything wrong. Being in the public eye, especially, can be hard sometimes. It’s kind of like anything you do is . . . if you make any mistake . . . It can definitely be overwhelming sometimes.”

After Waiting for Anya, he will be seen in Abe, in which he plays a Jewish boy from Brooklyn who cooks to unite his half-Israeli and half-Palestinian family, and Hubie Halloween, with Adam Sandler. And, of course, there’s the small matter of reuniting with the rest of the Stranger Things team.

“We’re going to start filming in, like, a month or so,” he says. “It’s very exciting to get back to work.”

Waiting for Anya is on release from February 21