London Film Festival‘s surprise film on Friday night was “I Play Rocky,” Peter Farrelly’s biographical drama about the beginnings of Sylvester Stallone‘s beloved boxing franchise.

Farrelly was on hand to introduce the movie and shouted out his star, newcomer Anthony Ippolito, who has already earned praise for his portrayal of Stallone. “I could do a TED talk about Anthony Ippolito. This kid is ridiculous,” Farrelly said, adding that the 27-year-old sent in a self-tape before the film team even began what was meant to be a “worldwide search” for who would play Stallone.

“He heard about the movie, tracked down the script, shot three scenes in his grandmother’s basement on Long Island and sent it to us,” Farrelly continued. “I looked at it like, ‘That’s it.’ We never looked past him.”

“I Play Rocky” tells the true story of how Stallone, then a young small-time actor, overcame obstacles to both write and star in the 1976 classic. Alongside Ippolito, it stars AnnSophia Robb as Sasha Czack, Stallone’s wife; Matt Dillon as his father, Frank Stallone Sr.; P.J. Byrne as “Rocky” producer Irwin Winkler; Jay Duplass as director John G. Avildsen and more.

Farrelly added that he’s most proud of the fact that Stallone himself is pleased with the movie. “No matter how well the movie does, how many people like it, if Stallone said, ‘I don’t like it,’ I would be really disappointed,” he said. “And he loved it.”

The film first premiered at Toronto Film Festival last month, where it was up for the People’s Choice Award and generated positive reviews. Variety‘s chief film critic Owen Gleiberman called the film a “cleverly-crafted crowd pleaser” and praised Ippolito for getting his portrayal of Stallone “just right,” writing: “Watching and listening to Anthony Ippolito, we can believe that Sylvester Stallone is standing right in front of us, though the performance is more than just an awesome impersonation. He’s truly playing Stallone — the sweetly stubborn and dogged person he was at the time.”

“I Play Rocky” is set to hit U.S. and U.K. theaters on Nov. 6.