Prince William on Thursday defended the British royal family after his younger brother Harry and wife Meghan accused them of racism in a bombshell interview watched around the world.

"We're very much not a racist family," William told reporters during a visit to a multi-racial school in a deprived area of east London.

The Duke of Cambridge, son of heir-to-the-throne Prince Charles, added that he had yet to speak to Harry in California since the interview first aired in the United States on Sunday.

"No, I haven't spoken to him yet, but I will do," he said.

A keenly awaited statement from Queen Elizabeth II issued Tuesday was conciliatory towards her grandson and his mixed-race spouse, after their interview with US chat show host Oprah Winfrey.

But it also stressed that "some recollections may vary", as Buckingham Palace vowed to look into the couple's assertion that an unidentified royal had asked how dark their unborn son Archie's skin would be.

Charles has yet to comment on the controversy but was filmed on Tuesday touring a Nigerian Christian church in London whose pastors are promoting a drive to vaccinate more black people against the coronavirus.

In the interview, Harry also said that his father and brother were "trapped" in a hidebound institution. (AFP)