A lawsuit claims the comedian, 48, exposed himself to the woman on set before forcing her to perform sex acts on him in a bathroom stall.
Brand has faced a series of serious accusations from a number of women, with Met Police confirming they are investigating claims.
The comedian was accused of one rape and sexual assault when four women made allegations to the Sunday Times and Channel 4’s Dispatches programme.
A slew of further claims then emerged as women revealed their stories to newspapers and the BBC.
Brand has vigorously denied allegations made against him.
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Now, a lawsuit has been filed against Brand accusing him of sexually assaulting a film extra – named only as Jane Doe – on the New York City set of the 2011 romantic comedy Arthur.
It marks the first accusation against Brand leveled in court.
It was brought in state court under New York’s Adult Survivors Act, which gives accusers a one-year window to sue over alleged sexual abuse even if statutes of limitations have expired.
Jane Doe said she was hired to appear as a cast extra in July 2010.
The lawsuit claims Brand was drunk during production and exposed himself to Jane Doe as he sat at a table staring at her, “openly and obviously in the presence of everyone on set”.
Jane Doe then claims Brand followed her into a bathroom where he forced her to perform sex acts on him.
The lawsuit says a production crew member stood directly outside.
The accuser says the assault caused “severe psychological injuries” and economic losses.
The suit seeks unspecified money damages from Brand on grounds of assault, battery, false imprisonment and infliction of emotional distress.
Warner Bros Pictures, which distributed Arthur was also named as a defendant – along with other companies involved in the film production.
They were accused of negligence and of aiding and abetting Brand by tolerating his misconduct on the set.