Elisabetta Grillo, 41, was taken ill and had to be led from the dock as evidence about her was given by her former colleague Alice Binks.
The defendant and her sister, Francesca Grillo, 35, are accused of abusing their positions by spending £685,000 on credit cards belonging to the celebrity couple to buy designer goods and luxury holidays for themselves.
Elisabetta returned to the courtroom after a
brief break, wiping her face with a tissue.
Ms Binks, who also worked as a personal assistant to Ms Lawson during her marriage to the multi-millionaire, said she often noticed the sisters wearing expensive-looking clothes and with designer handbags.
“Francesca would say that she got them from, like, a thrift shop or from eBay at a heavy discount,” Ms Binks, who now works for ITV, said.
“Elisabetta always had nice handbags. She would always say that they were from discount stores.
“They were always quite cagey and would sometimes get angry if you asked what they’d done at the weekend and were always quite secretive about their personal lives.”
Referring to one occasion with Francesca, Ms Binks said: “After pushing her for a while about what she’d done that weekend, it turned out she’d been to New York for the weekend, which was really weird because I’d never go to New York for just a weekend but she seemed to have a fun life and was kind of away a lot.”
Ms Binks, who worked for Ms Lawson from Oct 2010 to October last year, said she looked up the website where they claimed to have bought some realistic-looking fake designer goods, but did not think it was really where they were getting them from.
She added that Elisabetta — also known as Lisa — “could be quite difficult to work with”.
“She was quite bitter and quite angry,” she said.
“Most of the time Lisa would be on Facebook.”
Asked by Anthony Metzer, representing Elisabetta, if she had come to court to blacken his client’s name, Ms Binks said: “No, I like Lisa. I just came here to give evidence.”
Earlier Isleworth Crown Court in west London heard claims Ms Lawson has signed an exclusive deal to be interviewed by American chat show host Oprah Winfrey.
Karina Arden, representing Francesca, told jurors that the TV cook, who divorced Mr Saatchi earlier this year, would appear on the high-profile show next month as she cross- examined another personal assistant, Anzelle Wasserman.
“You know, don’t you, that Ms Lawson has signed an exclusive agreement with Oprah Winfrey in January?” Ms Arden asked.
“That’s not correct,” Ms Wasserman replied, but did not elaborate on what details were or were not accurate.
The Italian sisters each deny a single count of fraud.