A former MTV employee has told a jury she was left "in shock" after Russell Brand allegedly sexually assaulted her within minutes of meeting her at a Soho birthday party before leading her into a toilet cubicle.

Giving evidence through a recording of her police interview played at Southwark Crown Court, the woman said she had been excited to meet Brand at the Nordic Bar in 2004 after watching him on Big Brother's Big Mouth.

But she claimed the encounter quickly turned into something very different.

The woman alleged that Brand suddenly grabbed her breasts while they were talking at the busy central London venue.

Describing the moment, she said Brand had a "weird maniacal grin" and looked "like a clown" with a "weird look in the eye".

"I was completely in shock and was like, 'What the hell are you doing? I've literally just met you'," she told police.

The woman said Brand then took hold of her arm and led her towards the toilets.

Jurors heard details of what she says happened inside the cubicle, where she alleges Brand ignored her protests and repeatedly urged her not to be a "spoilsport".

The witness said everything happened very quickly and that she "froze", adding that she was left feeling unable to react.

Afterwards, she recalled Brand behaving as if nothing unusual had occurred.

"He was very much normal, just acting like nothing had happened," she said.

The woman, who is the third of Brand’s accusers to give evidence, said she told a friend about part of the encounter with the comedian, but “didn’t want to admit that I’d done it to anybody, because I feel like I probably could have stopped it, I don’t know”.

The court heard she later telephoned a male friend and disclosed part of what had happened. She said she downplayed the incident because she felt ashamed and did not want to think of herself as a victim.

"I wanted to change the narrative so I wasn't a victim in my head," she said.

The woman also told police she never reported the allegation at the time because she believed it would be her word against that of a rising television star during what she described as "those laddish culture times".

She said she later told close friends and avoided Brand whenever possible.

"Any time he was in the building, I just refused to go over or to any parties," she said. "If I knew where he was, I would just avoid."

Brand, 51, denies three counts of rape, three counts of sexual assault and one count of indecent assault. His defence is that all sexual activity was consensual.

The trial continues.