The double Oscar winner hit out at the claims by Graham Chase Robinson, who worked for him between 2008 and 2019, during an ill-tempered court hearing in New York.

Ms Robinson is suing De Niro for $12m (£9.9m) in damages for "severe emotional distress and reputational harm", claiming he shouted at her and called her abusive names.

The former employee, who was paid $300,000 (£247,000) a year, said she was also tasked with everything from decorating the star's Christmas tree to taking him to the hospital in the middle of the night when he fell down stairs.

Ms Robinson said De Niro refused to give her a job reference when she quit after repeated clashes with his girlfriend, Tiffany Chen. She also felt afraid to leave her house after leaving her role as the actor's vice president of production and finance.

Ms Robinson's lawyers also suggested Ms Chen was jealous of her partner's assistant, but said there was nothing romantic going on.

De Niro appeared to react angrily to the claims as he took to the stand on Monday, and raised his voice several times during his testimony.

The 80-year-old agreed he had listed Ms Robinson as his emergency contact and had relied on her with tasks such as helping with greeting cards for his children.

But when asked if he thought Ms Robinson had been a conscientious employee, he shot back: "Not after everything I'm going through now."

De Niro also raised his voice in apparent anger when his former assistant's lawyer suggested he had bothered her early in the morning to take him to the hospital in 2017.

He replied: "That was one time when I cracked my back falling down the stairs."

The actor said he went to bed after the accident, which happened at around 1am or 2am, and delayed summoning her until 4am or 5am.

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In another tense moment, Judge Lewis Liman intervened to explain the rules of testimony to De Niro and pointed out that there were limits to what he could say.

"Can I ask a question?" De Niro asked in another exchange with Ms Robinson's lawyer. The request was denied.

The actor, who recently starred in Martin Scorsese's Killers of the Flower Moon, insisted he treated Ms Robinson well even after he bought a five-bedroom Manhattan townhouse and let her oversee some of the preparations so he could move there with Ms Chen.

The actor continued: "It is not like I'm asking for her to go out there and scrape floors and mop the floor. So this is all nonsense."

Correspondence between De Niro and Ms Chen was also shown to jurors, in which his partner expressed suspicion about Ms Robinson's motives.

'Condescending, demeaning and abusive'

In one message, Ms Chen said she thought De Niro's assistant was acting like she was his wife, and believed that she had "imaginary intimacy" with him.

"She felt there was something there and she may have been right," De Niro told the court.

Ms Robinson's lawyers told the court their client never had a romantic interest in her boss.

Attorney Andrew Macurdy said Chen appeared to resent that De Niro relied on his assistant for so many tasks and that they communicated so well together.

He added: "There was never anything romantic between the two of them."

De Niro's lawyer, Richard Schoenstein, said Robinson was treated very well by the star "but always thought she deserved more."

He added that the actor was "kind, reasonable, generous," while his assistant was "condescending, demeaning, controlling, abusive" and "always played the victim."

The case continues.

The lawsuit comes only months after De Niro became a father for the seventh time, age the age of 79.

In July he spoke of his devastation after his grandson, Leandro De Niro Rodriguez, died aged 19 after allegedly being sold fentanyl-laced pills.