The Duke of Sussex, who currently lives in California, will not have enough time to quarantine for the full 10 days after arriving in the UK.
However, a provision in the the law will allow him to leave quarantine on "compassionate" grounds, which includes funerals.
The palace confirmed on Saturday the duke would be flying back to the UK, but the Duchess of Sussex, who is heavily pregnant with the couple's second child, has been advised by doctors against flying.
What do the rules say with regards to people attending funerals?
Government guidance, published online, states: “You can leave your place of self-isolation in limited circumstances, including on compassionate grounds.
“This includes attending a funeral of a household member, a close family member or a friend (if neither household member or close family member can attend the funeral).”
It adds: “You must continue to self-isolate at all other times.”
So what will Harry have to do to make sure he is complying with Covid-19 rules when he arrives in the UK?
Harry will have to take a Covid-19 test and return a negative result in the three days before travelling. He also needs to complete a passenger locator form with details of where he will quarantining.
He will also have to book a travel test package, which includes two coronavirus tests - one to be taken on or before the second day of his quarantine in the UK, and the second on or after his eighth day of quarantine.
He will need to book this package before travelling as he needs to include the package serial number on his passenger locator form.
Harry could also use the Test to Release scheme to pay for a private test from an approved supplier five days into quarantine. Tests cost around £130. He can leave quarantine if the result is negative.
Rule breaches face a fine of up to £10,000, and failure to take the required tests on days two and eight results in a £2,000 fine.
What are the Covid rules for funerals?
A maximum of 30 people are allowed at funerals under coronavirus rules. So the guest list will be slimmed down from the original plan of 800 guests.
A full guest list has yet to be announced, but the Queen, and Philip’s children and grandchildren will be on that list. Other relatives might also attend including the Queen’s cousins.
The Queen and her family will be required to wear face masks, and must socially distance from one another if they are not part of the same household, according to current guidelines.
This means Harry will need to be social distance himself from other guests, including his family.
Government guidelines state: “Stay at least two metres away from others outside your household or support bubble.”
The Duke of Edinburgh died at the age of 99 on Friday morning at Windsor Castle.
Harry and Meghan paid tribute to the duke on the website of their foundation Archewell, replacing its homepage with a memorial site and the words: “In loving memory of His Royal Highness The Duke of Edinburgh 1921-2021.
“Thank you for your service…You will be greatly missed.”