When asked if he was on 'Team Nigella' – the informal name for her group of supporters – the prime minister replied, "I am. I'm a massive fan."
He added, "I've had the great pleasure of meeting her a couple of times and she always strikes me as a very funny and warm person, but I’m also an amateur cook and I like her recipes.
"Nancy [his nine-year-old daughter] and I sometimes watch a bit of Nigella on telly. Not in court, I hasten to add," the Conservative leader said in an interview with the Spectator.
David's comments came as the 'Domestic Goddess's' trial against two aides, sisters Elisabetta and Francesca Grillo, revealed the extent of their spending.
On Tuesday Isleworth Crown Court heard details of Nigella and Charles Saatchi's personal spending from another personal assistant Anzelle Wasserman.
Anzelle told the court she had three bank cards she could use and that it was clear what the rules were when it came to personal spending.
"It was always a specific gift, it was never open-ended, buy yourself a gift," she said. "It was specific."
A list of payments on her staff credit card included £2,250 on cashmere jumpers for Nigella from Charles, £24,866 on flowers, £10,654 on VIP Glastonbury tickets for their children, £2,240 on Ralph Lauren homewares and £3,734 on wine for Charles from Annabel's.
An email from the accused Grillo sisters, who both deny fraud, was read out to the courtroom.
In it, they said: "We are at our utmost despair and we are reaching out to you in the sincere hope that somewhere in your hearts you will find a way to forgive us and believe that we never meant in any way to be seem to be disloyal or to seem like we took advantage of our positions.
"We truly believe that we had a bond like a family.
"You were, as you often said to us, our English family and we saw you like a mother and father figure in our lives over these 10-14 years that we have known you.
"There is not a worse feeling [than] thinking we have in any way let down our family and we are deeply sorry and full of regret.
"All we want to do is put this right and make amends."
Earlier in the trial the court heard claims that 53-year-old Nigella had a 'non-verbal' agreement with Francesca and Elisabetta in return for an understanding that they wouldn't leak details of her "daily" drug use.
Between 1 January 2008 and 31 December 2012 the Grillo sisters allegedly committed fraud by using the credit card for personal spending. They were arrested in August 2012 after Charles became aware of their spending.
Elisabetta, 41, and Francesca, 35, both of Kensington Gardens Square, Bayswater, west London, both deny the charges.
The Grillo sisters arrive at court
The duo were first employed by Nigella when she was married to her first husband journalist John Diamond, who died of throat cancer in 2001. Francesca and Elisabetta were described by Nigella as her "kitchen confidantes" in a dedication in a cookbook published in 2011.
Earlier this year she filed for divorce from her husband of 10 years on the grounds of his "continued unreasonable behaviour".
Their relationship came to an end after pictures were published of Charles holding Nigella's throat at a top London restaurant. Charles initially dismissed the incident as a "playful tiff" but later accepted a police caution for assault.
He told the Mail on Sunday that the pictures gave a "wholly different and incorrect implication". Nigella and Charles were estimated to be worth £150million together and previously shared an £11.8m home in Chelsea, London.
The trial continues.