This is why Pippa Middleton has virtually disappeared from the spotlight

Where she was once the most talked about woman in the world, second only to her older sister Kate, her rise to prominence was a sure thing. After gaining international fame as maid of honour at the royal wedding in 2011, there was a party planning book, columns with Vanity Fair and er, Waitrose, as well as a guest presenting gig on Good Morning America.

The future looked bright.

All were relatively short-lived and by 2016, she had retreated from public life completely, save for a few select charity appearances.

In the early days of Kate and Prince William's relationship, Pippa was steadfastly by her sister's side, in particular during their well-documented split in 2007.

It's believed Kate and Pippa are as close as ever and both play an active role in each other's lives, but it seems that after seven years, Pippa has finally adjusted to her overnight fame. While Kate never received any official guidance from the royals in the 10 years she was dating William before their wedding, she is now the family's crown jewel. Her sister, on the other hand, was experiencing intensified levels of scrutiny with little to no advice from the experts.

She was deemed fair game by the British press, who relentlessly criticised most of her professional endeavours - sometimes deservedly, sometimes not - which is reportedly one of the main reasons she has become increasingly clandestine.

It's not exactly clear how she fills her days, although she is often pictured exercising around London before returning to the £16million Chelsea mansion she shares with husband James Matthews.

Even her wedding last May to the multi-millionaire hedge fund manager was intended to be a private event as the media were not invited; but appearances by a number of royals in her inner circle, including niece Princess Charlotte and nephew Prince George's roles as flowergirl and pageboy all but guaranteed the world's press would descend on Bucklebury.

On the rare occasions Pippa does give interviews these days, it's for charity, in particular in conjunction with her role as an ambassador for the British Heart Foundation.

Royal expert Duncan Larcombe said it's part of her new life as a married woman, instead focusing on a quiet, but lavish, life with her husband of nearly one year.

"Much more so than Kate, Pippa has enjoyed the limelight over the years," Larcombe told Town & Country.

"I just think now she’s happy and happily married, settling down, not having to go to party after party or run these endurance events for charity. She seems to have put all of that behind her at the moment."

"She’s certainly still very much the socialite in terms of her circle of friends. A lot of her friends have gotten married and settled down, so I think these days she’s more likely to be hosting dinner parties in their lavish house rather than going out on the town and being photographed."

After a series of disastrous attempts for career independence, it's said her brother-in-law William took her under his wing and advised her on future career opportunities.

"It was felt by William in particular that she needed some guidance and support," the Daily Mail reported in 2016.

"Among some courtiers, there were also echoes of Sarah Ferguson, the Duchess of York, after her break-up with Prince Andrew and how she sold herself out with various corporate deals. It was felt something needed to be done. So Pippa has been quietly and diplomatically reined in."

It's not easy navigating royal-by-association fame, as Kate and Pippa's brother James (30) also knows. He has been dating tv presenter Donna Air for nearly four years and while they're often pictured out and about, he doesn't attract nearly as much attention as Pippa.

And his business hasn't replicated the success of their parents' party-planning company either.

In September 2017, his customised marshmallow company Boomf reported losses of £2.2 million, but is on the record as giving a lot more interviews to promote the business over the years, including with GQ, Good Morning America and the Daily Mail.

"It’s always been, whether at school or now, that I am Pippa and Catherine';s little brother. It’s probably going to be the story of my life. [But] I am James Middleton. I am very proud to be 'the little brother of…' but, equally, they are proud that I am who I am," he said in 2016.