Anton Yelchin Photo: IC

Below: The cast of Star Trek: Beyond (from left) Anton Yelchin, Chris Pine, Simon Pegg, Karl Urban, John Cho and Zoe Saldana Photo: IC

Co-stars, friends and fans added their voices on Monday to a chorus of tributes from Hollywood for Star Trek actor Anton Yelchin, after he was killed in a freak accident.

The rising star, best known for playing Chekov in the new Star Trek films, was killed by his own car as it rolled backwards in his driveway in the early hours of Sunday, police and his publicist said.

Susan Sarandon, who starred alongside Yelchin in the 2008 coming-of-age comedy Middle of Nowhere, described the Russian-born American actor, who was just 27, as "an original."

"One of the most curious, funny, sweet people I've ever known," she wrote on her Facebook page.

"He was a searcher, an incredible talent and a loyal and loving son. Any time would be too soon for his departure from this plane, but this is an unforgivable and unbearable loss."

Yelchin was preparing to meet friends for a rehearsal and momentarily got out of his car at his San Fernando Valley home, according to police.

It rolled backwards down his steep driveway, pinning him against a brick mailbox pillar and security fence. Friends later found him dead by the car.

Yelchin moved to the US when he was 6 months old with his parents, star figure skaters with the Leningrad Ice Ballet, and made his film debut at age 9 in A Man Is Mostly Water.

His breakout performance came in the 2006 crime thriller Alpha Dog, and his movie credits include J.J Abrams's Star Trek, Star Trek into Darkness and Star Trek Beyond, which is scheduled for release next month.

"You were funny as hell and supremely talented. And you weren't here nearly long enough," Abrams tweeted.

Star Trek co-star Zachary Quinto described him in a tribute on photo-sharing platform Instagram as "one of the most open and intellectually curious people I have ever had the pleasure to know.

"So enormously talented and generous of heart. Wise beyond his years, and gone before his time. All love and strength to his family at this impossible time of grief," he said.

Justin Lin, who directed Star Trek Beyond, paid tribute to Yelchin's "passion and enthusiasm."

Milla Jovovich, who acted opposite Yelchin in 2014 Shakespeare big-screen adaptation Cymbeline, described him as her "brother" and said she and her family were "destroyed" by his death.