Wednesday, US comedian Bill Cosby was freed from prison only hours after his sexual assault conviction was overturned by Pennsylvania's Supreme Court.

The judges indicated there had been a "process violation" by the prosecution, however, they admitted that the ruling was highly unusual.

Cosby, 83, served over two years of a three to 10-year prison sentence. Three years ago, he was found guilty of drugging and molesting Andrea Constand, a former basketball player.

He is best known for starring in the 1980s TV series The Cosby Show and was once known as "America's Dad".

One public confession of Cosby's assault became a catalyst for more accusations, with dozens of women coming forward to accuse him of sexual assault.

However, Cosby was only tried in court for Constand's case. His conviction in 2018 was widely seen as a catapult for the #MeToo movement.

In a verdict issued Wednesday, Pennsylvania's highest court found there was a "process violation" due to Cosby's lawyers making agreements with a previous state prosecutor that he would not be charged in the case.