Prince Harry will make the journey from the couple's home in California and will be following COVID-19 protocols for the trip and during his visit for his grandfather's funeral on April 17.

It is understood that Meghan, who is pregnant with her second child, had made every effort to join her husband but was not given clearance to travel by her doctor.

The Duke and Duchess of Sussex posted a tribute to Philip on the website of their foundation Archewell on Friday.

It reads simply: "In loving memory of His Royal Highness The Duke of Edinburgh 1921-2021. Thank you for your service...You will be greatly missed."

It was posted against a sombre brown background.

Harry has not returned to the UK since stepping down as a senior royal just over a year ago.

It will also be the first time he has seen his family in person since his and Meghan's bombshell interview with Oprah Winfrey, in which they accused the royal family of racism and the institution of failing to support Meghan.

The two-hour interview was aired while Philip was in hospital after having heart surgery.

The Queen issued a statement saying "while some recollections may vary" the issues would be taken "very seriously" but dealt with privately as a family.

Prince William, in a rare move on a royal engagement, spoke out publicly, saying "we're very much not a racist family".

Harry told Oprah that he felt let down by his father Prince Charles and that "there's a lot of hurt that's happened" between them.

Only 30 people will attend Philip's funeral at Windsor Castle as guests, expected to be his children, grandchildren and other close family.

Currently, funerals can be attended by a maximum of 30 people in the UK due to COVID-19 restrictions.

Mourners coming from outside England are required to self-isolate for 10 days after they arrive.

But Harry will be entitled to leave his place of self-isolation on compassionate grounds to attend the funeral.

He could also be released from quarantine if he gets a negative private test on day five, as per government rules.

Australian Associated Press