The interview will air for UK viewers on Monday 8 March at 9pm on ITV.
Just about every aspect of the royals’ recent history has been thrust back into the limelight, with comparisons made between the treatment of Meghan Markle, and that of Diana, Princess of Wales 25 years previous.
One name that has popped up again is James Hewitt, the former cavalry officer with whom Diana admitted engaging in an affair in the mid-90s.
But who is Hewitt? Where is he now? And what does he do?
Here is everything you need to know about him.
Who is James Hewitt?
Born in Derry, Northern Ireland in 1958, and raised in Kent and Devon, James Hewitt became nationally famous around the time of another televised royal tell-all – that of Diana, Princess of Wales in 1995.
The now infamous 55-minute Panorama broadcast was clearly the deciding factor in influencing the Queen to urge her son and his estranged wife to divorce, and arguably set in motion a chain of events that would ultimately end in tragedy.
The Martin Bashir interview was seen as an attack on both Prince Charles and the royal family, with Diana arranging the interview in secret without even telling senior members of her Kensington Palace household.
The princess called royal officials “the enemy” and questioned the Prince of Wales’ suitability to be King.
But she also confessed to adultery with Hewitt, and said of Charles’ affair with Camilla Parker Bowles, now the Duchess of Cornwall: “There were three of us in this marriage, so it was a bit crowded.”
How did the affair start?
Hewitt had been asked to give Diana riding lessons while still a member of the Household Cavalry, and it was at this time that his affair with the princess began.
Within months, details of the relationship had leaked to the press, and the affair was being regularly reported on by British newspapers; most notably a full-story expose in the News of the World.
Fuller coverage of Hewitt and Diana’s relationship came in 1994, when Anna Pasternak – now a regular Daily Mail contributor – published her best-selling book, Princess in Love.
Hewitt – having left the army – was a major source for the book’s research, alleging that his affair with Diana had taken place over five years from 1986 to 1991.
After the affair came to an end, Hewitt said he considered suicide, telling US entertainment show Inside Edition he “loaded a few things up to get on the ferry to go to France – to shoot myself”, only putting pause on the plans when his mother “insisted on coming with me”.
Almost 30 years removed from the couple’s affair, rumours still swirl in some quarters that Hewitt, and not Charles, is the biological father of Prince Harry.
This theory is often discredited by Royal experts; Hewitt has stated that Harry had already been born by the time of the affair, and Diana attributed Harry's red hair colouration to her side of the family – yet theorists remain.
Where is he now?
Following Diana’s death, Hewitt attempted to sell his collection of personal letters from the princess for £10 million, an act that was condemned by many members of the Royal Household as a betrayal of trust.
In 2004, he was arrested for the possession of cocaine and was given a warning, and was also refused reinstatement of his firearms licences after police found a disassembled 16-bore shotgun on his living room floor.
13 years later, Hewitt reportedly suffered both a heart attack and a stroke in 2017, leaving him fighting for his life – he was released from hospital just over a month later, and was said to be recovering well at home.
Now, the 62-year old is reportedly working as a £4,000-a-year gardener in the grounds of the flat he lives in with his elderly mother.
According to the Daily Mail, Hewitt was recently seen driving a mower and raking leaves on the Devon estate, but according to some fellow residents, has made a “dog’s dinner” out of some of the garden’s more notable features.
One resident claimed Hewitt had damaged a historical Yew tree in an attempt to "make it look regal and shape it like a wine glass".
"It looks like an octopus," said 71-year old neighbour, Mrs Presswell.