New York's highest court on Thursday overturned disgraced Hollywood producer Harvey Weinstein's 2020 conviction on sex crime charges, a shock reversal in one of the defining cases of the #MeToo movement.

In its 4-3 decision, the Court of Appeals found the trial judge had erred in admitting the testimony of women who were not named in the charges brought against Weinstein, and ordered a new trial.

The ruling however doesn't affect a separate 16-year rape sentence, handed down in California in 2022, meaning the once-untouchable Hollywood heavyweight will remain behind bars.

"The accused has a right to be held to account only for the crime charged and, thus, allegations of prior bad acts may not be admitted against them for the sole purpose of establishing their propensity for criminality," Judge Jenny Rivera wrote in an opinion for the majority.

Bombshell allegations broke against the Academy Award winning producer in 2017, launching the #MeToo movement that paved the way for women to fight back against sexual violence in the workplace.

Weinstein, 72, had been convicted in a New York court in February 2020, of the rape and sexual assault of ex-actress Jessica Mann in 2013 and of forcibly performing oral sex on former production assistant Mimi Haleyi in 2006. He was later sentenced to 23 years in prison.

"The news today is not only disheartening, but it's profoundly unjust," said a statement from The Silence Breakers, a group of women who banded together to report Weinstein's misconduct. "But this ruling does not diminish the validity of our experiences or our truth; it's merely a setback."

Weinstein was also convicted by a Los Angeles court -- and sentenced to an additional 16 years in prison -- for the rape of a woman in a Beverly Hills hotel room. That sentence was originally supposed to be served after his New York sentence.

"The legal system has never served survivors in this country," #MeToo founder Tarana Burke told reporters, though she added that "because these brave women in this case broke their silence, millions and millions and millions of others found the strength to come forward."

"That will always be the victory."

Following his conviction in New York, a civil trial awarded $17 million to dozens of other women who had accused the former movie magnate of abuse.

Weinstein is not the first high-profile man convicted in the wake of the #MeToo movement to have his conviction overturned.

Comedian Bill Cosby was found guilty in 2018 of drugging and sexually assaulting a woman, but Pennsylvania's supreme court found he was denied a fair trial and set him free.

"With today's decision, this Court continues to thwart the steady gains survivors of sexual violence have fought for in our criminal justice system," Judge Madeline Singas, who dissented against the ruling, said.

"Forgotten are the women who bear the psychological trauma of sexual violence and the scars of testifying again, and again."

The Court of Appeals' decision to overturn the conviction rested on the fact the trial judge allowed prosecutors to rely on so-called "Molineux witnesses," who were allowed to testify about their experiences despite not being part of the charges brought against the defendant, in an exception to the normal rules surrounding evidence.

Attorney Douglas Wigdor, who represented two such witnesses, said: "The jury was instructed on the relevance of this testimony, and overturning the verdict is tragic in that it will require the victims to endure yet another trial."

Before the allegations against him emerged, the producer and his brother Bob were Hollywood's ultimate power players.

They co-founded Miramax Films, a distribution company named after their mother Miriam and father Max, in 1979. It was sold to Disney in 1993.

Their hits included 1998's "Shakespeare in Love," for which Weinstein shared a best picture Oscar. Over the years, Weinstein's films received more than 300 Oscar nominations and 81 statuettes.