Jinele McIntire claims she was involved in an altercation with Sizemore after he invited her to his home on 22 June (10) to discuss child support payments for their two sons, according to legal documents filed in Los Angeles County Superior Court.
McIntire alleges the Saving Private Ryan star "punched me in the face and head repeatedly. My ear started bleeding. (He then) punched me in the stomach with such great force, it took my breath away".
She also claims Sizemore "threw a long knife (it looked like a kitchen knife) on the floor of the bathroom."
A judge granted the restraining order on 30 June (10) but a spokesperson for Sizemore has denied the allegations, branding them "100 per cent untrue".
The rep tells TMZ.com, "(The account was) completely fabricated and made in the attempt to discredit Tom Sizemore... because (McIntire) thought Tom was plotting to take the children."
McIntire filed suit against Sizemore in October (09), accusing the actor of leaving her to single-handedly raise their twins boys, who were born in 2005.
Sizemore has a growing list of legal woes - he was charged with spousal battery following his arrest for an alleged attack on a woman in August (09) and was found guilty of assaulting then-girlfriend Heidi Fleiss in 2003.
He was also arrested last year (09) on an outstanding warrant for drug charges.
A week after Tila Tequila, Jason Wahler and rapper Bizzy Bone signed up for the new season of Celebrity Rehab, the show has been postponed.
TMZ.com reports producers failed to land enough big name stars to front the hard-hitting show.
The programme was scheduled to start shooting on Tuesday (01Jun10).
Reports suggest Lindsay Lohan turned down $1 million (£666,600) to appear on the show.
Past stars who have checked in for Celebrity Rehab have included Daniel Baldwin, Gary Busey, Heidi Fleiss, Mackenzie Phillips, Dennis Rodman and Mindy McCready.
The Saving Private Ryan actor was jailed for 17 months in 2005 after failing drug tests while on probation for assaulting his then girlfriend, Hollywood madam Heidi Fleiss, two years earlier (03).
And Sizemore reveals he endured life behind bars by focusing on his love of The Bard - writing down excerpts from his favourite plays and reciting them to keep his "brain working".
He tells U.S. newsman Larry King, "I didn't do drugs in prison. I focused on not losing myself. There wasn't a lot of fighting. I had to fight a few times and I can handle myself. I'll take a beating, I don't care.
"But in prison, it's different. Taking a beating could be your last beating. I know Shakespeare a lot. I know it well. I remember full plays almost. I've (a) really great memory. I wrote down as many of the plays I've been in that I can remember the lines that I had and other characters I had. I wrote down the movies I had been in.
"I wrote them out to make sure my brain was still working and to keep myself - I have a good imagination, I could disappear into (acting)... When I played Iago (in Othello), I still know what I did when I was 21."
The troubled actor has battled substance abuse since the late 1990s, but managed to secure roles in high-profile movies including Saving Private Ryan and Black Hawk Down.
In 2002, he landed a part in Mann's TV cop series Robbery Homicide Division, which instantly won praise from critics, but the show was cancelled after 10 episodes, ending the following year (03).
Although the series failed to compete with rival police programme Law & Order: Special Victims Unit in the ratings, Sizemore is convinced the show was axed following his arrest for assaulting his then-girlfriend, Hollywood madam Heidi Fleiss.
And the star insists he reached his darkest days when his boss and pal Mann wouldn't speak to him.
In an interview with U.S. newsman Larry King, he says, "Michael Mann wouldn't return any of my phone calls. He's a great director, but he was my friend... I fell a great distance. Michael, if you see this, I'm very sorry.
"(My lowest point was) calling the office and the gentleman (on the phone), saying, 'Tom, he just doesn't want to talk to you'. I mean over and over. The first time I went, 'Why?' Well, I know why, because of what I was doing. I said, 'Tell him I need to (speak to him)'.
"It wasn't (that) he was being mean... He was angry about the show being cancelled, Robbery Homicide Division, which was one of the greatest crime dramas ever made.
"I was the star of it and I got arrested during it. That may have cancelled it. Who knows? I have a great deal of guilt about that and I'm very sorry for it, but it happened.... Michael was my friend. He wasn't a director guy I worked with."
The 62-year-old actress is currently starring in British reality show Celebrity Big Brother, alongside Stephen Baldwin, Sisqo, Ivana Trump and former Hollywood madam Heidi Fleiss.
And when glamour model Nicola T told the group she thought the ex-brothel boss was "the most interesting person I think I've ever met in my life," Beacham was quick to reveal her own scandalous dealings.
She told her shocked housemates, "Highest I've ever been offered for a night is 40 grand."
But actor Baldwin misheard the 62 year old, naively enquiring, "Forty pound?"
To which a disgruntled Beacham insisted, "Forty thousand."
The TV veteran is reportedly receiving a $160,000 (£100,000) fee for her stint on the show.
The former model, who was rumoured to have walked away with a $24 million (£15 million) settlement when she divorced the business tycoon in 1991, is the new surprise addition to Britain's Celebrity Big Brother.
Singer Sisqo was performing a magic show during a variety performance task, when he unveiled the socialite in place of his original assistant, British rapper Lady Sovereign.
The Thong Song hitmaker joked, "I meant to do that. You see, I really am a magician."
Trump, who famously said of her split from Donald, "Girls, don't get mad, get everything," is currently divorcing her fourth husband, 37-year-old Rossano Rubicondi.
She has joined a line-up of celebrities including Vinnie Jones, Stephen Baldwin and former Hollywood Madam Heidi Fleiss, who all entered the house last Sunday (03Jan10).
The soccer star-turned-actor is currently competing on U.K. series Celebrity Big Brother alongside other stars including Stephen Baldwin, Sisqo and former Hollywood Madam Heidi Fleiss.
And the Kill Bill filmmaker, who befriended Jones in 2007, has praised his pal for carving out a successful career in Hollywood since giving up life on the soccer pitch.
He says, "If the winner (of Celebrity Big Brother) is judged on personality and character, then Vinnie can be the only winner. He is one of the most charismatic guys in Hollywood and people who know him not only know that he is a fantastic person but that he has a heart of pure gold. I'm honoured to call him my friend.
"He might still be known as Vinnie Jones the soccer player in Britain but he is a real movie star now. He has starred in some of the most ground-breaking films of the last 15 years. He has worked with the best directors and starred alongside some of the world's most famous actors and he never once looked out of place."
And Tarantino is convinced Jones only entered the show because he wants to take his mind off his soldier son Aaron, who is currently serving in Afghanistan with the British army.
He adds, "People often put themselves forward for reality shows because they are broke or want to revive their career, but Vinnie is neither of those things. He is going to get some time away from worrying about his son Aaron. He is very proud of not only Aaron but all his family, but like any other father he worries - that is only natural. I don't know about the other contestants, but Vinnie Jones is a real superstar."
Prior to entering the house, Jones spoke out about his fears for his son, admitting the thought of him fighting in the war-torn country "turns your tummy."
The star's sibling Jason was holidaying in Hawaii over the Christmas (09) period but was swept out to sea by a strong current on 28 December (09).
Fleiss was left devastated by his shock death - which happened just two days before her 44th birthday.
But she will miss his funeral as she is participating in British reality show Celebrity Big Brother.
Her fiance Dennis Hof says, "Heidi was so devastated she almost pulled out of Celebrity Big Brother.
"She said, 'I loved Jason. I don't want to be disrespectful to him.' I told her she needed to get away and stay busy so she does not have time to dwell on this awful thing."
The 44 year old revealed her motherhood nightmare to Stephen Baldwin and British actress Stephanie Beacham on Britain's Celebrity Big Brother.
Asked if she had any children, Fleiss, who was once engaged to actor Tom Sizemore, revealed she was convinced she would be a bad mother - and is all in favour of terminations.
She said, "I hope I never have babies. That would kill me. Every minute I'd be, 'Is the baby OK?' I'd worry too much.
"Thank God for abortion. I don't mean to offend anyone but I wouldn't be a good mother. I shouldn't have kids."
But her comments have been met with outrage by viewers in Britain, with several taking to unofficial Big Brother forums to voice their anger at her views.
One online poster called Fleiss a "stupid b**ch," while another urged fellow fans of the show to vote her off, scrawling, "Get her out!"
The former Madam has started off 2010 doubling up as a reality TV star on both sides of the Atlantic Ocean - she also appears on Celebrity Rehab with Dr. Drew in America, where she comes face to face with her ex, Sizemore, who was jailed for abusing Fleiss.
Baldwin, who has starred in a string of U.S. reality shows in recent years, including I'm a Celebrity... Get Me out of Here! and Celebrity Apprentice, was first into the house on Sunday (03Jan10).
He was quickly joined by Dynasty legend Stephanie Beacham, British rapper Lady Sovereign, and Sisqo, who performed an impromptu rendition of hit track Thong Song before he began his stint under the watchful eye of the TV cameras.
Other stars, including former Hollywood madam Heidi Fleiss and Ronnie Wood's ex-girlfriend Ekaterina Ivanova, entered the house before Jones arrived.
Producers are obviously hoping for a stormy series - also starring in the show are British singer Dane Bowers and his ex Katie Price's new boyfriend Alex Reid, who were allegedly involved in a New Year's Eve (31Dec09) brawl at a party in Surrey, south east England.