” I’m so sorry it took me 9 years to understand why he left[HARRY] ” Prince Williams sobbed bitterly and vowed not to success the throne as he leaves royal home over outrageous act by Camila and her son Tom Parker

In less than three weeks, one of both Prince William and Prince Harry’s closest friends will tie the knot in the social event of the season.

Billionaire Hugh Grosvenor, the Duke of Westminster, and his fiance, Olivia Henson are set to wed on June 7 in Chester, in England’s north-west, in front of the who’s-who of British aristocracy.

Just as conspicuous as the future King’s appearance at the event will be his brother’s absence – and new details have shed light on exactly how the awkward invitation scenario played out behind the scenes.

The UK’s Times revealed on Sunday that not only is William attending as a guest – with his wife, the Princess of Wales, likely to stay home amid her cancer treatment – but he has also been honoured with a role as an usher on the day.

Meanwhile, Harry, who has been close friends with Hugh – or “Hughie” as he’s known within his inner circle – since childhood and even appointed him as his son Prince Archie’s godfather, was reportedly kept from the guest list to avoid any discomfort.

(Sources close to Harry and his wife, Meghan Markle, have previously disputed their lack of invitation, insisting that they had received a “save the date card” but declined attendance as it would be “too awkward”.)

According to the Times, Hugh had been keen on both brothers coming to his nuptials, but was conscious that their high-profile rift could overshadow the festivities, and had therefore deciding against inviting the Sussexes.

When their looming absence was first reported last year, a friend of the warring brothers described the situation as “incredibly sad”.

“It’s incredibly sad it has come to this. Hugh is one of the very few close friends of William and Harry’s who has maintained strong bonds and a line of communication with both,” the source told the Times.

“He wishes they could put their heads together and patch things up, but realises it’s unlikely to happen before the wedding. He wanted to avoid anything overshadowing the day, especially for Olivia, and doesn’t want any awkwardness.”

There’s been no sign of any easing of tension between Harry and William, with the latter reportedly still furious about his brother’s heavy public criticism of himself and Kate since leaving royal duties.

Meanwhile, Harry’s absence at the Duke of Westminster’s wedding may be the most high-profile, but he’s not the only royal unable to attend.

King Charles, who is the duke’s godfather, is also likely to skip the occasion. The monarch, who recently returned to public-facing engagements during his cancer treatment, will be travelling to France alongside Queen Camilla and William for D-Day commemorations the day prior.

Regardless, it’s still on track to be a lavish event, with over 400 guests invited to witness the nuptials at Chester Cathedral.

Following the service, guests will attend an opulent reception at the Grosvenors’ nearby 11,000-acre estate, Eaton Hall, the couples’ new home.

On June 8, a second, more intimate reception will be held at the same venue.