According to the report of The Hollywood Reporter, Sizemore continued his shooting in Malibu after a few months when the young actress' parents refused to expose him with the help of the press.
In the story posted online on Monday, November 13, a dozen cast and crew confirmed the incident to THR, saying that it took place towards the end of filming Born Killers, which is about two brothers on a crime spree.
The actress, whose name was not released at her request, told The Hollywood Reporter she declined to comment on the alleged incident but has "recently hired a lawyer to explore legal action against the actor as well as her parents".
The 55-year-old actor is said to have battled drug addiction since he was 15, and has been convicted of domestic violence and drugs charges. She added that afterward, "the young girl had trouble taking direction".
THR reported Sizemore is said to have denied the young actress' claim as soon as he was confronted with it; shortly after, he was quietly dropped by his management firm and talent agency.
The Hollywood Reporter further details the alleged incident occurred during a photo shoot involving the young actress, who is now 26 and wishes to remain anonymous.
"The mother noticed that her daughter was unusually quiet and told her she was going to take her to this swimming place that was the little girl's favorite thing", McGregor recalled.
She said: "Later, when I was told about what happened, I knew exactly what it was".
His representative Stephen Rice's told them: "Our position is 'no comment'".
Sizemore is said to have strongly denied the little girl's allegations when he was confronted over the allegations at the time, telling producers: "I've done a lot of terrible things, and I'd never do anything with kids".
However, the next day the girl told her mother, who communicated concerns to producers through the girl's agent.
"It filtered down to the crew", Roi Maufas, who worked as a production assistant, told the outlet. "He was this guy who was already known for making inappropriate comments, being drunk, being high".
"They did talk to the police but didn't press charges", producer Michael Manshel told the paper. "We're talking about consistent behaviour, just being 'Tom Sizemore" on set every day.
The film's producers dismissed Sizemore from the set as soon as they heard the claim and reviewed the photographs from the photo shoot but found them inconclusive. "Then this happens. [A producer] had to stop a group of us from going to visit Mr. Sizemore to kick the guy's ass".