Over the last decade at the Toronto International Film Festival, I've spoken to a number of young actors who've gone on to impressive careers. Dakota Fanning, Saoirse Ronan, and the new Spider-Man, Tom Holland, all gave mature interviews well beyond their years.

In September, the latest young performer to join the list was Lewis MacDougall, who's been wowing critics in the intense J.A. Bayona grief drama A Monster Calls, opening Friday.

There's a fair amount of death surrounding A Monster Calls, the story of Conor (MacDougall), learning to cope with the terminal illness of his mother (Felicity Jones) through the thunderous, fablelike stories of a scary tree (voiced by Liam Neeson) that comes to life outside his window.

The movie is based on a story by prizewinning children's author Siobhan Dowd, who was dying of cancer when she wrote it (it was finished by prizewinning children's author Patrick Ness). MacDougall took on the role when he was 12, not long after his own mother had died.

"I did draw from my own experiences," he said, reticently mentioning his mother's multiple sclerosis. "But although there are things that did overlap with our two experiences, the two situations - what Conor goes through and what I went through - are different. I could, however, empathize with some of the stuff he was going through, and that did help me."

MacDougall, from Edinburgh, Scotland, got his start acting in a local drama group, through which he was cast as Nibs in director Joe Wright's 2015 film Pan, one of the many recent variations on J.M. Barrie's Neverland sprite.

"Through Pan I got my agent, and from there I was asked to do an audition in London [for A Monster Calls]," he said. "It wasn't really a massive thing."

It soon became massive.

"I got called back to do another audition in London where I met Bayona (The Impossible), and I was quite nervous, as you can imagine," MacDougall said. "This was only my second audition process ever. Then I got called to go to Barcelona for a screen test. There were four or five other boys there, and, despite the competitiveness, I got on quite well with them.

"That screen test was the first time I ever got really emotional - like Conor does in the film."

It worked. MacDougall found out while on holiday that he got the part. "I was ecstatic," he said.

"Before we started shooting, I did two weeks of motion-capture in Oxford with Liam," MacDougall said. "And although my character's obviously not CGI, I was there reading the lines with Liam, and that was good fun."

Then there was a month of shooting exteriors in Manchester (in the U.K., not Casey Affleck's by the sea) and then three months in Barcelona, where Bayona is based.

MacDougall said it was a long shoot, made longer by the work restrictions he faced as a young actor.

"Because I'm a child means that the hours are different and I have to fit in tutoring," he said. "But I did have a great time in Barcelona because I had my weekends free."

His screen mom Jones (Rogue One, The Theory of Everything) and tightly wound screen grandmother Sigourney Weaver (Alien, Ghostbusters) couldn't have been more helpful or nicer, MacDougall said.

"I really respect them because of how they conducted themselves on set," he said, "and because they treated me as their equal despite being way more experienced than I am."

In addition to his smaller, one-on-one scenes, MacDougall enjoyed the experience of being a modern-day movie actor in a high-tech CGI world.

"With the monster," he said, "sometimes it was just me acting to a tennis ball on the top of a pole, for my eye line. But they actually did make a massive monster face and it was extremely realistic and you see it in the film. They could make the mouth move and the eyes lit up, and that really helped me."

In scenes in which the earth moves beneath MacDougall's feet, the now 14-year-old said that was not all CGI. The earth literally moved.

"They made a platform of land maybe 20 or 25 feet high but they could control it from underneath with all the different sections moving," he said. "Obviously, whenever I was on this platform I was wearing a harness."

After A Monster Calls, MacDougall shot the road-movie dramedy Boundaries, slated to open later this year, this time with Vera Farmiga as his mother and Christopher Plummer as his grandparent. But for the most part, he said, "I go to school and lead a pretty normal life. My friends aren't really that astounded by it.

"But they haven't seen A Monster Calls yet."