The Duke of Edinburgh passed away "peacefully" at Windsor Castle on April 9, Buckingham Palace confirmed on Friday.
To honour the late royal, US-based Harry and Meghan updated their website, Archewell.com, on Friday afternoon, to share a message reading: "In loving memory of the Duke of Edinburgh" and the years 1921-2021.
The website also said: "Thank you for your service...You will be greatly missed."
The Duke and Duchess of Sussex famously stepped away from the royal family in early 2020 and relocated first to Canada before settling in California.
According to Harry, the pair were keeping in touch with his grandfather via video calls in recent months.
Will Harry and Meghan return to the UK?
Harry is expected to make his first trip back to the UK since cutting ties with the royal family to attend his grandfather's funeral, a source told the New York Post.
"Harry was extremely close to his grandfather," the UK royal source told the publication. "He will, of course, be there, no matter how difficult relations are between the Sussexes and the family."
It's thought that Meghan, who is due to give birth to their second child in the northern summer, will not make the 12-hour flight and instead remain at their LA home with their son, Archie.
Flying when pregnant can be safe but tends to be advised against after the 37th week according to the NHS. Some airlines will require doctors' notes if the woman is 28 weeks pregnant or more.
All travel corridors were suspended by the UK in February due to the COVID-19 pandemic, meaning those arriving in the country need to quarantine for 10 days. However as the US is not on the UK's red list, quarantine does not need to be done in a government-approved hotel.
Harry and Meghan would have to present negative coronavirus tests during their quarantine according to the government regulations. There are exceptions given on compassionate grounds, for which a funeral would qualify.
Earlier this year, the Duke and Duchess of Sussex sat down for an interview with US chat show host Oprah Winfrey in which they laid bare their grievances with the royal household.
The bombshell tell-all aired while the ailing Duke of Edinburgh was still battling an infection in a London hospital. The 99-year-old was admitted on February 16 before being moved to a second hospital two weeks later.
There, he had surgery for a pre-existing heart condition. After what became a month-long stay, Prince Philip was discharged and returned to Windsor Castle to be reunited with his wife, the Queen on March 16.
Harry and Meghan faced criticism for the timing of the interview but claim they did not have any control over the decision.
While they did make some significant claims about their time as senior royals, including an allegation of racism, they exonerated the Queen and Prince Philip from those allegations.
Meghan also indicated she was still close to the Queen despite the huge physical distance, saying she had "picked up the phone" and called her when she heard the news in February that Philip had gone into hospital.
Staying in touch
In an earlier interview with friend and talk show host James Corden, Harry had revealed he had been keeping up with the Queen and Philip via video calls, and that the great-grandfather had been able to watch Archie playing in their new Californian home.
But he died before he was able to meet his 11th great-grandchild, as the Duchess of Sussex has not yet given birth to her second child, a girl.
Asked about whether the Queen can use Zoom, Harry said: "Both my grandparents do, we have Zoomed them a few times.
"They've seen Archie running around. But my grandfather instead of pressing leave meeting, he just goes 'doof'," he said miming closing a laptop.
Additional reporting by Rebecca C Taylor.
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