Despite his few public appearances in the past year, including Prince Harry and Meghan Markle's wedding, fans across the globe have asked:
What happens when Prince Philip dies?
The news will first be confirmed by British broadcaster the BBC and the Royal Family via their social media channels.
Should his death happen overnight, the announcement is likely to come at 8am London local time.
Eight days of official mourning would be observed by all staff at the palace.
Flags across the UK at major institutions and military establishments with a focus on naval flags given Prince Philip's ties with the Royal Navy would be flown at half-mast.
While the Duke is entitled to a state funeral, it is believed that he'd
prefer not to have the "fuss" of a lying-in-state or a full state funeral.
It's expected that instead of Westminster Abbey, Prince Philip's body will lie at St James's Palace.
His body will not be viewed by the public.
Prince Philip will be laid to rest in Frogmore Gardens, in the grounds of Windsor Castle.
This means he might not be buried with his wife, as many of Britain's monarchs and consorts are laid to rest in Westminster Abbey and St George's Chapel.
Should the Duke pass before his wife, the Queen is allowed an official mourning period of eight days.
All royal affairs will be put on hold during this time, out of respect for Her Majesty's loss.
She will be allowed a further 30 days to mourn her life partner, before being expected to make a full return to public life and duties.