The Duke of Cambridge has said the royals are "very much not a racist family" in his first comments after accusations by the Duke and Duchess of Sussex in a TV interview.
Prince William also said he had not yet spoken to his brother but would do so.
Meghan and Prince Harry said a royal had expressed concern over "how dark" their son Archie's skin might be.
Buckingham Palace previously said the claim was "concerning" but it would be addressed privately.
In a statement, the Palace said "recollections may vary" but that the Sussexes would "always be much loved family members".
During a visit to a school in Stratford, east London, on Thursday, Prince William was asked by a reporter: "Is the Royal Family a racist family, sir?"
The duke replied: "We're very much not a racist family."
Asked whether he had spoken to Prince Harry since the Oprah interview, Prince William said: "No, I haven't spoken to him yet but I will do."
Prince William's visit is not the first appearance by a senior royal since the interview aired - the Prince of Wales carried out an engagement earlier this week.
BBC royal correspondent Sarah Campbell said Prince Charles would have avoided questions about the interview - but "clearly Prince William felt strongly enough to feel that he had to address the issue and he did so quite directly".
"There have been headlines across the world intimating that the Royal Family is racist so this is the first time that one of the senior members has come out and really rebutted that."
In the TV interview, Meghan told Oprah there were "concerns and conversations about how dark [Archie's] skin might be when he was born".
Both Prince Harry and Meghan refused to say who made the comment - but Harry later clarified to Oprah that it was not the Queen or the Duke of Edinburgh.
During the interview Harry also said it hurt him that his family never spoke out about the "colonial undertones" of news headlines and articles.
And asked by Oprah if the couple left the UK because of racism from the tabloid media, Harry replied: "It was a large part of it."
In the interview, Harry also spoke about his relationship with his family - especially with his father, the Prince of Wales, and brother Prince William.
At one point after stepping back as senior royals, Harry said Charles "stopped taking my calls".
And of William, Harry said: "The relationship is 'space' at the moment. And time heals all things, hopefully."
Buckingham Palace issued a response to the interview earlier this week following crisis meetings involving senior royals.
Figures from US TV network CBS suggest that nearly 50 million people around the world have watched Oprah's interview with the couple.
The fallout from the interview has also seen broadcaster Piers Morgan leave his role as host of Good Morning Britain, after his comments about Meghan attracted 41,000 complaints.
Meanwhile, the head of the Society of Editors - an industry body for the UK press - resigned after a row over its reaction to Harry's comments about the tabloid media.