A US court overturned comedian Bill Cosby's conviction for drugging and sexually assaulting a woman 15 years ago on Wednesday, allowing his release from prison.

"Cosby's convictions and judgment of sentence are vacated, and he is discharged," the Pennsylvania Supreme Court wrote in a 79-page ruling.

The 83-year-old, most famous for his role on hit TV series "The Cosby Show," has served more than two years of a three-to-ten-year sentence for aggravated indecent assault.

It was not immediately clear when he would be released.

"We will need to receive, authenticate and review the court documents before we move forward," a spokesperson for the Pennsylvania Department of Corrections told AFP.

Cosby was convicted in 2018 of assaulting Andrea Constand at his Philadelphia mansion.

It was the first guilty verdict for sexual assault against a celebrity since the advent of the #MeToo movement.

An earlier prosecution ended in a mistrial in June 2017 after the jury was unable to reach a unanimous verdict.

Although more than 60 women charged that they had been victims of sexual assault by Cosby, he was tried criminally only for Constand's assault, since the statute of limitations had expired in the other cases.

He filed his second appeal against his conviction in August last year.

His lawyers argued that five women should not have been allowed to give evidence at his trial as witnesses.

They complained that their "decades-old" allegations, which were not part of the charges, had prejudiced the jury.

The attorneys also argue it was "fundamentally unfair" that deposition testimony Cosby gave in a civil case regarding his use of sedative drugs and his sexual behaviors in the 1970s was heard in court.

They argue that Cosby believed the testimony was immune from prosecution when he gave it.

Cosby had lost an earlier appeal when a court ruled that the prosecution's evidence had established Cosby's "unique sexual assault playbook."

Megatrix:
There was never any evidence against him. This jury people just decide cases based on emotions, I don't know where the US got this there useless trial by jury method. Many innocent people are languishing in jail just because members of jury that know nothing about the law decided to find them guilty based on emotional sentiments.

Megatrix:
There was never any evidence against him. This jury people just decide cases based on emotions, I don't know where the US got this there useless trial by jury method. Many innocent people are languishing in jail just because members of jury that know nothing about the law decided to find them guilty based on emotional sentiments.