Fans of The Crown will have noticed a new family brought into sharp focus this season as the Mountbattens make it to the small screen.
In the fifth series of the Netflix show, viewers follow not only the lives of Royals but also their relationships with close friends and aides.
Among those to come to the fore are Penny and Norton Knatchbull, the Earl and Countess Mountbatten of Burma, and their daughter Leonora.
We take a look at the true story behind this family and their links to the House of Windsor.
Who are the Knatchbulls?
Norton Knatchbull is the 3rd Earl Mountbatten of Burma and 8th Baron Brabourne.
Born in 1947, he was a school friend of King Charles at Gordonstoun in Scotland, the godson of Prince Philip, Duke of Edinburgh and the grandson of Louis, the 1st Earl Mountbatten of Burma.
His ancestral home is Broadlands in Hampshire, where the Queen and Prince Philip spent their honeymoon.
After finishing his education, he worked as a film producer and in 1979 married Penelope Eastwood, the daughter of Reginald Eastwood who founded the Angus Steakhouse chain.
She was born in London in 1953, was educated in Switzerland and graduated from the London School of Economics.
Their marriage came just months after the IRA bombing in County Sligo which killed Norton’s brother Nicholas, his paternal grandmother Doreen Knatchbull, Dowager Lady Brabourne, his maternal grandfather Louis Mountbatten and Paul Maxwell, a 15-year-old boy from County Fermanagh who was working as a crew member.
The couple have three children: Nicholas born in 1981, Alexandra born in 1982 and Leonora born in 1986 and three grandchildren.
Leonora died, aged five, of kidney cancer and the family founded a cancer charity in her name.
In 2010, it was revealed the then Lord Brabourne had left his wife and moved to the Bahamas while conducting an affair with the fashion designer Lady Eugenie Nuttall.
The affair ended in 2014 and he returned to the family home of Broadlands and remains married.
He is reported to be suffering from ill health, with the Countess now running the family estate.
Why they play a part in The Crown
Focus on the family in this season of The Crown comes from both Lord Mountbatten’s close friendship with King Charles and Countess Mountbatten’s with Prince Philip.
From the first episode of the season, we see Prince Charles, played by Dominic West, confide his marriage troubles to Norton Knatchbull played by Elliot Cowan while they are away together on a joint family holiday in the Mediterranean.
A scene from Leonora’s funeral also sparks the start of a close bond between Penelope Knatchbull, played by Natascha McElhone and Prince Philip, played by Jonathan Pryce.
The Duke of Edinburgh is seen encouraging the Countess to take up his latest hobby carriage driving as a distraction from her grief at the loss of her daughter.
Netflix refers to The Crown as a fictional dramatisation of real events.
Although it is uncertain whether any of these events actually happened, King Charles has remained close to the Mountbattens becoming godfather to their son Nicholas and walking their daughter Alexandra down the aisle when she married in 2016.
While the Countess was a lifelong companion to Prince Philip competing with him in carriage driving, a confidante during and after his retirement from royal duties and one of only 30 mourners to attend his funeral in 2021.