[5] After graduating from the Royal Military Academy Sandhurst, Hewitt was commissioned into the Life Guards, British Army, on 8 April 1978 as a second lieutenant.

[14] The BBC reported in 2003 that in retirement, Hewitt was granted the rank of major which was "in line with common army practice".

He also appeared in the first episode of the UK Top Gear in Series 8 in May of the same year to participate with other celebrities in setting power lap times around the Top Gear Test Track in the show's newest "reasonably priced car": when the presenters seemingly did not recognise him upon his arrival, they were apparently too embarrassed to admit as much, and rather than ask him his name, they listed his lap time as "Well Spoken Man".

[17] In 2009, Hewitt opened a bar called the Polo House in the fashionable Golden Mile of Marbella, Spain.

The following year, the film Princess in Love by David Greene was released, based on the book, with Julie Cox and Christopher Villiers playing the lead roles.

"[23] Persistent suggestions have been made in the media that Hewitt, and not Charles, is the biological father of Diana's second son, Prince Harry, Duke of Sussex (born 1984).

Hewitt stated to the press in 2002 that Harry had already been born by the time of the affair,[24] a statement also made by Diana's royal protection officer, Inspector Ken Wharfe.

He reiterated this in an interview in 2016,[25] again in 2017[26] and in his memoir Diana: Closely Guarded Secret published in 2002 (and reissued in 2017) in which he says "A simple comparison of dates proves it is impossible for Hewitt to be Harry’s father.

As a result, he was refused reinstatement of his firearms licences because of his "intemperate habits" after police found a disassembled 16-bore shotgun on his living room floor.