Nigella Lawson told a court today she would rather be "honest and ashamed" than "bullied with lies" after revealing details of her past drug use.
The TV cook said she was "not proud" after admitting she has taken cocaine and cannabis but denied her admission was "damage limitation".
"I'm not proud of the fact I have taken drugs but that does not make me a drug addict or a habitual drug user," she said.
Ms Lawson said she objected to stories "peddled" by her ex-husband Charles Saatchi, including that he was checking her nose for cocaine when he was photographed gripping her throat outside Scott's restaurant in central London.
"The fact is, I would rather be honest and ashamed... I wasn't going to be bullied with lies," she said.
"Mr Saatchi was not examining me for cocaine. That's a story he made up afterwards to clear his name."
Ms Lawson was continuing her evidence in the fraud trial of two of her former personal assistants.
Wearing an all-black outfit, she was greeted by a huge pack of photographers, reporters and cameramen as she arrived for a second day at Isleworth Crown Court in west London.
Jurors were previously read an email sent to Ms Lawson from Mr Saatchi in which he said the defendants would "get off" on the basis that she was "so off her head" on drugs she allowed them to "spend whatever they liked".
Yesterday Ms Lawson denied being a drug addict and spoke of the "intimate terrorism" she suffered at the hands of Mr Saatchi.
She said she first took the class A drug with her late husband John Diamond when he found out he had terminal cancer, and on another occasion later during her troubled marriage to Mr Saatchi.
But the 53-year-old, who also admitted to smoking cannabis, said the idea that she is a "drug addict or habitual user of cocaine is absolutely ridiculous".
"I did not have a drug problem, I had a life problem," she said.
Francesca Grillo, 35, and her sister Elisabetta, sometimes referred to as Lisa, 41, are accused of committing fraud by abusing their positions by using a company credit card for personal gain.
Prosecutors claim the Italian sisters lived the ''high life'', spending the money on designer clothes and handbags from Louis Vuitton, Christian Dior and Vivienne Westwood.
The pair are accused of using credit cards loaned to them by the TV cook and her ex-husband to spend more than £685,000 on themselves between 2008 and 2012.
The Grillo sisters, of Kensington Gardens Square, Bayswater, west London, deny the charge against them.
Under cross-examination by defence barrister Karina Arden, representing Francesca, Ms Lawson denied using her evidence to explain herself in front of "the world's press".
"I felt it was my duty to come," she said.
"I certainly felt it would be an unpleasant experience but that's not a good enough reason not to do one's duty.
"I prefer to keep my private life private."
Ms Lawson denied lying to police when she disputed the drug allegations against her and said it was the "extent" of her drug use that was untrue.
"It was not true in that my ex-husband was saying that he was getting cocaine out of my nose at Scott's and that I had been completely off my head for 10 years," she said.
"I actually did say at the time it was the extent that was not true."
She told the court her first use of cocaine with Mr Diamond was in 1999.
Referring to her admission of drug use yesterday, Ms Arden put it to Ms Lawson that it was "a case on your part of damage limitation".
Ms Lawson replied: "No, I was asked the question and I responded."
The celebrity cook, standing in the witness box wearing the same high-heeled boots as yesterday, took issue with Ms Arden referring to her as "the lady of the house".
Repeating the term back to the barrister, Ms Lawson said: "I don't think it is the job of a woman to run a house."
She said it was the job of herself and Mr Saatchi.
When asked if the multimillionaire Saaatchi Gallery owner really had an interest in the house, Ms Lawson said: "Absolutely. He would go round and point out marks he wanted removed.
"He is a person with a tremendous eye for detail."
Ms Lawson said that among other duties, Francesca would organise Mr Saatchi's frappuccinos and sew buttons on his suits.
Ms Arden asked if Francesca did the food shopping, to which Ms Lawson replied: "I do a fair amount myself."
Ms Arden then said: "This is no criticism of you as a domestic goddess."
Speaking about giving presents to her staff, Ms Lawson said she did so "to show gratitude or because I like them, and it pleases me to give presents when I can afford it".
When asked by Ms Arden if she felt it was important to keep her team happy, Ms Lawson said: "You must always thank someone for doing a good job. It's not enough just to pay them.
"Everyone in life needs to feel appreciated."
Ms Lawson said she tried "as much as possible to foster a friendly atmosphere at work", but added that it "wasn't always possible" and that there were "some hostilities".
Ms Lawson said she "became involved" with Mr Saatchi after Mr Diamond died.
"It would be fair to say that not very long after my first husband died I began to become involved with Mr Saatchi," she said.
The court heard that Francesca took a number of holidays with Ms Lawson's children and stepchildren, including trips to Paris, Berlin, New York, Los Angeles and the south of France.
Ms Lawson said Mr Saatchi was "very much a cash man" and would have given Francesca money to take on the trips for their children.
Ms Arden asked about an instance when Francesca was called while on holiday.
She said: "There was one occasion when you couldn't find the remote, you contacted her in Spain."
Ms Lawson replied: "Yes, that would have made Mr Saatchi very irritable."
The food writer admitted there were "no written-down rules" about the use of Mr Saatchi's company credit card by the PAs.
"It was known, because it was spoken, that they were not for personal use except if directed," she said.
Ms Lawson said she would occasionally treat staff by browsing online to find an item they wanted.