A top lawyer says Lady Susan Hussey also question him about his heritage at the same event where she asked a black charity boss if she came from Africa.
Nazir Afzal, former chief crown prosecutor for the North West, was at the Buckingham Palace this week with Ngozi Fulani when she was questioned about her ethnicity by Lady Hussey.
Ngozi, who runs a black women's domestic abuse charity in London, took to Twitter to share how the late Queen's friend touched her hair and asked her where "in Africa she comes from".
Less than 24 hours later, the palace confirmed that Lady Hussey had stepped down from her role following the racist remarks.
Mr Afrzal, who recently led the review that found the London Fire Brigade to be institutionally racist and misogynistic, has said he was also asked about his ethnicity by Lady Hussey, who is also Prince William's godmother.
He tweeted: "I was at the Buckingham Palace reception at which Lady Hussey questioned the heritage of a brilliant DV expert Ngozi Fulani.
"She only asked me my heritage once & seemed to accept my answer - Manchester currently! Racism is never far away tho."
Hussey, 83, was one of the late monarch's most trusted friends.
Yesterday a palace spokesman said in a statement that they "have reached out to Ngozi Fulani on this matter, and are inviting her to discuss all elements of her experience in person if she wishes".
However, speaking on ITV's Good Morning Britain today, Ngozi denied claims by the Palace that someone had reached out to her.
She told hosts Ben Shephard and Kate Garraway: "I don't know where this is coming from but I'm telling you categorically we have not heard from the Palace."
It comes after Ngozi exclusively told The Mirror what Lady Hussey did was racist and that she left wanting to flee the event.
Ngozi told the Mirror: "[What she did] was racism. Through and through. It was prolonged racism.
"The fact that it was just done in the open in front of people, on a day when we should be working towards violence against women."
Hussey also said: "I can see I am going to have a challenge getting you to say where you're from. When did you first come here?"
Eventually, Ngozi says she replied: "I am a British national, my parents came here in the 1950s," before Hussey responded with: "Oh, I knew we'd get there in the end, you're Caribbean."
Ngozi says she then corrected the aristocrat by responding with: "No, I am of African heritage, Caribbean descent and British nationality."
She added: "I just wanted to leave, I felt very unwelcome. I've never lived anywhere else, I've only lived in Britain.
"So someone to come and tell me, someone, who has been in the royal household for her to kind of just insist that I'm not British.
"Those were not her words but that's the implication. I don't know how to process that."
Ngozi said she felt "very unwelcome" and "attacked' but added that she did not want Hussey to lose her job and that instead, she wanted institutional change.
Ngozi said she was "blindsided" and the experience left her feeling like she had "been knocked back decades".
Prince William has also commented on the claims made by Ngozi.
His spokesperson said: "I was really disappointed to hear about the guests' experience at Buckingham Palace last night.
"Obviously, I wasn’t there, but racism has no place in our society.
"The comments were unacceptable, and it is right that the individual has stepped aside with immediate effect."
Meanwhile, Prince William and Kate's royal tour in the US has been overshadowed by the palace race row.
Yesterday, the Prince and Princess of Wales were met with some 'boos' while attending a professional Basketball game.
The visit to the United States for the prize is their first overseas engagement since becoming Prince and Princess of Wales in September.
The Earthshot tour has been overshadowed after William's godmother and senior courtier Lady Hussey was forced to resign over comments to a black woman that have rocked the monarchy.
