1:20 PM PT -- De Niro's attorney, Tom Harvey, tells TMZ ... the allegations made by Robinson "are beyond absurd."
9:12 AM PT -- Robinson's entered an angry voicemail from De Niro as an exhibit in the lawsuit. On the message, De Niro says, "You f**king don't answer my calls? How dare you?? You're about to be fired. How dare you?"
He makes reference to Robinson wanting a new position, and then rips into her with ... "Don't f**king get angry with me 'cause I'm pissed off 'cause I didn't get a simple thing that I need right now ... you gotta be f**king kidding me, you spoiled brat! F**k you!"
Robinson doesn't reveal in the lawsuit when De Niro left the voicemail.
Robert De Niro is being sued by a former assistant who claims he made sexually charged comments to her, was verbally abusive and assigned her "stereotypically females duties" ... a lawsuit she filed after he sued her.
According to a new lawsuit, obtained by TMZ, Graham Chase Robinson claims she was hired by the actor in 2008 as his executive assistant. The then 25-year-old claims De Niro communicated to her in a "hostile, abusive, and intimidating manner" and referred to her as "a bitch" and "a brat." She claims De Niro referred to a female business partner as a "c***."
She also claims De Niro was often intoxicated and would lash out at her. He would also joke with her about his Viagra prescription, and would ask her to "imagine him on the toilet."
De Niro allegedly suggested Robinson could get pregnant by using sperm from a male coworker.
De Niro actually sued her first back in August, claiming she watched 55 episodes of "Friends" during a 4-day period and used the company credit card to get fancy lunches.
Robinson has other complaints in her lawsuit, alleging De Niro urinated during phone calls with her and ordered her to scratch his back and prod him awake when he was sleeping. She also says De Niro stood "idly by" when one of his friends slapped her on the butt.
Robinson is suing for gender-based harassment, back wages and damages of at least $12 million -- which happens to double De Niro's suit against her, for $6 mil.