A former Cosby
As Cosby walked toward court, accompanied by two publicists and a police escort, Nicolle Rochelle climbed over a barrier and began shouting.
The words “Women’s Lives Matter” and the names of Cosby’s accusers were written in red and black lettering on her bare torso.
Uniformed officers wrestled her into the bushes and on to the ground as Cosby’s entourage followed a few steps behind.
After a minor delay, he proceeded into court where opening arguments were due to take place after pretrial issues were resolved.
Ms Rochelle was charged with disorderly conduct and could be fined if convicted.
The 39-year-old appeared in four episodes of The Cosby
The international women’s movement Femen claimed responsibility for organising the protest, saying Ms Rochelle was one of its activists.
Cosby, 80, played the witty and beloved patriarch on The Cosby Show.
The accuser in the case, Andrea Constand, 44, is one of more than 50 women who have accused him of sexual assaults, some dating back decades.
Cosby has said the encounters were consensual.
Ms Constand’s case, dating to 2004 when she was an administrator at Temple University, Cosby’s alma mater, is the only one to go to criminal trial.
Cosby facing up to 10 years in jail
If convicted of aggravated indecent assault, Cosby could face up to 10 years in prison.
The trial, which is being held at Montgomery County Courthouse in Pennsylvania, is expected to last about a month.
A seven-man, five-woman jury was selected last week.
In June, the first jury failed to come to a unanimous verdict on charges that Cosby drugged and assaulted Ms Constand at his home outside Philadelphia in 2004.
Judge Steven O’Neill declared a mistrial.
The retrial unfolds against the backdrop of the global #MeToo movement.
A parade of women have ended years of silence to tell their stories of sexual misconduct and assault by powerful men in Hollywood, politics and business.