Nicole Contreras, the former girlfriend of Mel B's estranged husband has revealed how he narrowly escaped jail after being prosecuted for trying to choke her during a jealous outburst.
Stephen Belafonte allegedly pinned Contreras, 41, against a wall and screamed at her before she managed to get away and call police, the Daily Mail reports.
The estate agent said he branded her a "b****" and a "whore" and even said she was "fat" when pregnant with their daughter, Giselle, now 12.
She also said he was abusive, controlling and regularly flew into jealous rages during their turbulent five years together.
In reality, Miss Contreras said, he was the one who was cheating - allegedly bedding up to 12 women, including the former Spice girl, behind her back.
Miss Contreras, a former bikini model, told The Sun that she texted Miss Brown this week in support as the abuse allegations emerged.
Any testament from Miss Contreras could help prove Miss Brown's claims and prevent him from taking part of her £48 million fortune.
She said Belafonte also attacked her in 2003 - four years before he married the pop star, adding "there is no lid to his fury."
Referring to the alleged assault, Miss Contreras said: "Stephen grabbed me by the arms and pushed me against the wall. His hands were digging into my arms and he was really hurting me."
"He was inches from my face and screaming at me. I could feel his hot breath on my cheeks. I was frightened and begged him to stop. But Stephen wouldn't - he put his arm across my neck and had me in a choke hold. I was struggling to breathe. I knew I had to escape. I screamed for him to get off me. Somehow I managed to get away and call 911."
Belafonte was charged with battery and received a suspended jail term. He was also ordered to attend a year-long domestic violence programme and stay away from Miss Contreras.
The former bikini model, who met Belafonte in a Hollywood nightclub in 2000, said she wished she had warned Miss Brown about her ex partner.
"He is abusive, controlling and manipulative, as well as a narcissist and a sex addict," she said. "He would go through my phone and fly into a rage if he didn't know what I was doing, or he thought a man was trying to talk to me. When he is angry there is no lid to his fury. He needs help."
Miss Contreras also claimed Belafonte urged her to have threesomes with her friends - but she always refused.
A furious Mel B has teamed up with her estranged husband's ex-girlfriend with a pledge to "take him down" and protect the former Spice Girl's £50 million fortune, The Mail on Sunday can reveal.
The pact was agreed after Mel B, 41, made a flurry of "tearful and emotional" phone calls to Nicole Contreras. They both claim that Hollywood producer and director Stephen Belafonte subjected them to a ruthless campaign of emotional and physical abuse.
Ms Contreras, 40, a former model, has a 13-year-old daughter with Belafonte as a result of their six-year relationship, which ended just months before Mel B met him in February 2007.
"I will do anything I can to help Mel in her fight," she said. "I know better than anyone what she has gone through because I lived with him for six years and he abused me too. We both went through hell with that man."
Ms Contreras, now an estate agent in LA, claims she is still "terrified" of Belafonte, 41, who was accused of beating her up in 2003, but vowed: "Mel called me asking for help. She was emotional and tearful. We have spoken multiple times this week. I will do whatever it takes to help her."
A source told this newspaper that Mel B had hired forensic accountants to go through her financial records for the past decade.
"It's all about money now. Stephen took control of the finances and Mel believes he siphoned off millions. Mel knows Nicole will be a powerful ally to have in what will undoubtedly be a vicious and nasty fight ahead.
"Nicole suffered abuse at this man's hands and she and Mel have vowed to take him down and make sure no other woman is hurt."