Tom Sizemore Behind-the-Scenes Footage from Last Feature Film Before Death

Tom Sizemore's work on his last feature film before he died was much like a heavyweight champ giving it his all despite being past his prime ... so says his director on the project.

The late actor plays a police detective in Bruce Bellocchi's upcoming flick, "The Legend of Jack and Diane," in what turned out to be Tom's final movie role ... and TMZ got this behind-the-scenes footage of Tom on set.

As you can see in the clip, Tom's super engaged with the director and his costars as he prepares to shoot a scene as Detective Parker.

Tom was 60 when he filmed the movie, and Bruce says he looked much older than that, was often hunched over and looked very tired all the time. However, he adds ... "That being said, he was professional and I thought always gave his best."

The movie's about a young couple, Jack and Diane, in Indiana who are planning to move to L.A. when they suddenly discover secrets about the death of Diane's mother ... and once their worst fears are confirmed, they create a hit list to get revenge on everyone involved.

Tom's scenes were shot on location in and around L.A. and production wrapped in March 2022 ... about a year before Tom's death.

TMZ broke the stories ... Tom suffered a brain aneurysm at his home in February and was rushed to a hospital, where he was placed on life support. He never regained consciousness and his family ultimately made the difficult decision to remove him from life support.

He died on March 3.

The director says Tom called him a few months after production wrapped and apologized, saying he wasn't sure he gave his best work. But, Bruce says he assured Tom his performance was great.

Bruce summed up the experience with a vivid sports metaphor ... "It was like getting into the ring with the heavyweight champ and although you knew he was past his prime, it was still a surreal experience just to be able to share time together."

The director says he and Tom had a lot in common, telling us they "shared many nights in deep conversation about battling past demons and having the will to keep moving forward."

Bruce is upset the Academy omitted Tom from its 'In Memoriam' segment during the Oscars and believes they snubbed an actor who turned in some of the finest performances in modern cinema.