She said: "I was scared at the time nobody was going to believe me. I didn't want to make a scene. I just wanted to go home."
Piven, 52, has denied all of the recent allegations made against him.
In a statement, he told BuzzFeed: "Let me be absolutely clear, this simply did not happen.
"I would never force myself on a woman. I cannot speak as to why a person would create a story like this."
Meanwhile, HBO said: "We reviewed our records and did not receive any complaints against Jeremy Piven on Entourage.
"HBO takes sexual harassment very seriously and we make it a priority to ensure that everyone experiences a safe and comfortable work environment."
The latest accusation comes shortly after Piven passed a lie detector test which questioned whether he had "fondled" Ariane Bellamar.
The former Entourage star previously denied sexual assault accusations made by the actress and two other women, Amy Meador and Tiffany Bacon Sourby.
And Piven is said to have passed all of the tests in a bid to prove his innocence.
The actor reportedly took polygraph tests regarding the three claims, and a blanket lie detector test to determine if he had ever assaulted a woman, and he passed with no signs of deception.
- Bang! Showbiz
