TORONTO -- Growing up in the outskirts of Montreal, actor-filmmaker Xavier Dolan says he worshipped stars like Natalie Portman, Kathy Bates and Susan Sarandon.

Then he got to direct them.

The Cannes-feted director's "The Death and Life of John F. Donovan" centres on a years-long correspondence between a young boy and a famous actor that ends up altering both their trajectories.

To tell this cautionary tale about the constraints of celebrity, Dolan cast several of his childhood idols, including a trio of Oscar winners in Portman, Bates and Sarandon.

"It makes you very emotional to feel like you're now at a time that you can work with these people that you once admired and now share creative things with them," Dolan told a group of reporters last September at the Toronto International Film Festival.

Nearly a year later, the film is set to open in Canada on Friday, after a path to a limited release that proved to be its own showbiz drama.

Backed by a $35-million budget and an all-star cast, Dolan's first foray into English-language cinema has been dogged by production troubles: a prolonged editing process resulting in the excision of A-list actress Jessica Chastain; a last-minute pullout from the 2018 Cannes Film Festival; a critical panning upon its premiere at TIFF; and difficulty securing a release in North America (a date still hasn't been set in the U.S.).

The first cut of "The Death and Life of John F. Donovan" clocked in at more than four hours, according to Dolan, who spent two years in an editing suite trimming the film down to feature length.

"I think the reason that it's been in post-production for so long is that I wanted to pay tribute to a lot of the films (and TV shows) that mattered to me as a kid," said Dolan.

"I wanted to include all these darlings from my childhood, which became hard when I had to make choices."

For all his indecision, Portman said Dolan was exacting in his attention to detail, making changes as minute as the way a background extra opened a newspaper.

Portman said this meticulousness helped her refine her performance as the mother of an aspiring child actor, played by Jacob Tremblay, who establishes a pen-pal relationship with TV star John F. Donovan.

"It was incredible to get to watch this person who's significantly younger than myself have such a formed vision of how he wants to create this world," Portman said of the 30-year-old director, whose acclaimed films include 2014's "Mommy."

"Game of Thrones" star Kit Harrington, who plays the film's titular character, said Dolan's dedication motivated him to push his limits as an actor. But as the Montreal shoot wore on, Harrington admitted Dolan's tirelessness could at times be "frustrating."

Harrington remembered a conversation with Dolan after filming an extended trailer for his character's supernatural teen drama "Hellsome High."

"(I'm) like, 'This is a whole day of shooting, Xavier. I know you're never going to use this,"' he recalled. "He's like, 'Yes, but I need it.' (And I said), 'But you don't! You really don't! I could have gone home three weeks ago.'

"I think in some ways, that's the way he works. He has a big melting pot of ideas, he throws them all into one, and then he works it out almost as a puzzle afterwards."

At the heart of the film is a coming-of-age story, said Dolan, which in some ways, parallels his own trajectory from child actor, to cinematic wunderkind, to directing the stars who shaped his cultural upbringing.

Dolan has since returned to his roots with the French-language independent film "Matthias et Maxime," which premiered at Cannes in May and is set to be released in some Canadian cities on Oct. 9.

As for his future in Hollywood, Dolan said he never saw "The Death and Life of John F. Donovan" as his entree into the world of celebrity.

"I have no destination. I have no agenda," he said. "I want to work with actors and artists that inspire me, whether I'm acting with them, or for them or directing them. That's all that matters to me."

"The Death and Life of John F. Donovan" hits theatres in Toronto, Vancouver, Calgary and across Quebec on Friday.