Heather Mills insisted today she treated her former nanny "like a daughter".
Giving evidence at an employment tribunal brought by Sara Trumble, the former model said they got on so well she had been asked to be godmother to Ms Trumble's child.
Ms Trumble, 26, is seeking compensation from her former boss on the grounds of sex discrimination and unfair dismissal and claims she suffered changes to her employment terms following her maternity leave.
The former nanny told the hearing in Ashford, Kent, today that Ms Mills made the lives of all her staff a misery but she was the only one prepared to speak out.
But giving evidence, Ms Mills said: "I treated Sara like my daughter as she often complained that her mother was cold and distant to her.
"I spent much of my time consoling her, especially when she said she was having problems with her partner."
Ms Mills said that after her nanny had her baby "she asked me to be godmother to her daughter".
"She said it was because I had taken such good care of her and she could think of no one better. I was delighted."
Ms Mills added that she now has three godchildren.
She said she met Ms Trumble when she was a beauty therapist at a health club in Rye, East Sussex.
"She gave me a great massage when I was seven months pregnant. I said she was great and purposely booked in Sara from then on, especially when she said she was only earning an average of £20 a week.
"I tried to think of ways she could earn more money and said maybe when my baby was born she could babysit to supplement her income."
Ms Mills said she and former husband Sir Paul McCartney took Ms Trumble on as a nanny.
She told the hearing: "She was not a qualified nanny, more of a babysitter/childminder.
"She suggested we could do beauty treatments too.
"Sara's duties were very varied as with all my staff. Everyone just mucks in and helps out when needed.
"At no time when she worked for me did she ever question this."
Ms Mills said she gave Ms Trumble £1,500 after she had some money stolen and also £500 for a deposit on a flat when she wanted to move out of her parents' home.
Ms Mills said she gave Ms Trumble lots of gifts and baby things when she had her daughter, including her breast pump.
She said she was very accommodating when she wanted to work only part-time after having the baby.
She said: "This did not suit my needs particularly but I understood, having a daughter of my own and knowing the dilemmas parents face."
She said Ms Trumble handed in her notice "out of the blue".
"I was surprised and disappointed. Although I wanted her to give me four weeks notice, I agreed to her request that she could have two weeks."
She said of the childminder, who looked after daughter Beatrice when she was in the US: "Lydia had helped out when she was on maternity leave.
"Lydia confirmed she would be happy to come over to help out for a while.
"I called her myself and left a message saying that we were planning a leaving party.
"Lydia was not asked to come to the UK until after she had resigned. She was not replaced by anyone and I still do not have a full-time nanny."
Ms Trumble has told the tribunal panel that Ms Mills forced her to say positive things about her to a film crew and made her work long hours without extra pay.
She also claims her former employer made her feel uncomfortable by moaning to her about ex-husband Sir Paul and was unsympathetic when she went though a difficult pregnancy, forcing her to accompany her on trips abroad.
During cross-examination by Ms Mills's solicitor, Caroline Crampton-Thomas, on the second day of the hearing, Ms Trumble said: "I wasn't the only person who felt that at that time. It's just that nobody else will stand up. I decided to take action and fight this for myself."
Ms Trumble, who was paid £260 a week to look after Beatrice, now six, said she was close to Ms Mills when she began working for her in April 2004 but she became rude and bad-tempered after she split from the former Beatle.
She told the tribunal that all of Ms Mills's staff, which included her housekeeper, her personal trainer Ben Amigoni, a bodyguard and her personal assistant, noticed a change.
She said: "Everyone was saying how difficult working conditions had become at at work. (It was) not a nice place to work."
She added that they were all under pressure to make sure Ms Mills's new nine-bedroom home in Robertsbridge, East Sussex, was ready after it was refurbished in August 2007.
"Things had to be perfect for when Heather came back. Everyone was rushing around stressed."
Ms Mills, who sat at the back of the room wearing thick-rimmed glasses, a grey pinstripe suit jacket, black trousers and a pink shirt, whispered to friends throughout the hearing.
She also kept angrily walking over to speak in her solicitor's ear, at one point prompting her sister Fiona to tell her to sit down.
Ms Trumble, of Westfield, admitted she asked Ms Mills to be godmother to her daughter Lily when she was born in September 2007.
She was also questioned over claims that she received a £10,000 pay-off from Sir Paul after she resigned in September 2008.
She said the money was a gift "for my dedication and hard work with Beatrice" and she declined it "several times" before eventually accepting.
"Paul did not want anybody to know that he gave me this money. I don't want to get Paul involved so it's difficult to talk about this money," she said.
She said Ms Mills made her feel "awkward" by making her lie to Sir Paul about where she was when she met him to collect or drop off Beatrice.
Ms Trumble also described how at these times Ms Mills would send out her new boyfriend, Jamie Walker, to flaunt him to her ex-husband.
Ms Trumble admitted that Ms Mills was often generous towards her, giving her several monetary gifts along with a Daihatsu Copen convertible car, as well as baby clothes and accessories.
She also acknowledged that Ms Mills took her to Slovenia with her other staff and friends to celebrate her 39th birthday and she was invited to join the charity campaigner on a holiday to Sir Richard Branson's private Caribbean island, Necker, although she did not go as she had only just had her baby.
But she disputed that Ms Mills took her on numerous shopping trips for clothes, adding: "She bought me one top, and on another occasion it was a 'buy one, get one free' top she bought me."
Questioned about why she wanted to leave the job, she said: "It's not all about money, I'm not talking about gifts and all that she gave me. It's about how she treated me."
Asked by Ms Crampton-Thomas why she refused to sign a further confidentiality agreement after she resigned, Ms Trumble said she felt she did not need to as she had already signed numerous forms.
She denied she had ever gone to the press and said she did not know who was responsible for an article which appeared about her in the Sunday Mirror.
"I had nothing to do with the press during my employment with the McCartneys," she said.