Prosecutors in the US have charged comedian Bill Cosby with aggravated indecent assault over an alleged incident in 2004.

It is the first time Mr Cosby, 78, has been charged with any offence after months of accusations.

Andrea Constand says she was drugged then assaulted at the Philadelphia home of the former US television star.

Dozens of women have accused him of sexual assault, dating back to the 1970s, but he has denied wrongdoing.

Mr Cosby made no comment as he arrived at court to be formally charged. He did not enter a plea at the hearing where a judge set bail at $1m.

Later, his lawyer said in a statement that he would "mount a vigorous defence against this unjustified charge".

Prosecution allegations

Single charge of aggravated indecent assault

Incident occurred at Cosby's home in 2004

Victim "frozen, paralysed, unable to move"

Charge punishable by five to 10 years behind bars and a $25,000 fine

Will formally be charged in court on Wednesday

Earlier this month Mr Cosby opened a lawsuit against seven of the women, accusing them of defamation.

It is the second time there has been an investigation into Ms Constand's complaint against the actor, who won acclaim for playing a family doctor and model father in The Cosby Show.

In 2005, after no charges were brought when she first made the accusation, she sued him and settled for an undisclosed sum.

He has previously said under oath he had a consensual sexual encounter with her.

How Cosby 'drugged his victim' - what the criminal complaint says

Mr Cosby befriended Ms Constand through her job at Temple University and she came to think of him as "a mentor and a friend" before he allegedly made two sexual advances that were rejected, said prosecutors.

Documents from her lawsuit against the star were sealed until this summer, when damaging testimony was revealed as more women came forward.

The 12-year statute of limitations was only days away from expiring, in January 2016.