We could never imagine Will without Kate and now, Harry without Meghan, but it turns out history could have played out very differently.
In fact, Prince William and Prince Harry could have ended up with high-society ladies Isabella Calthorpe and Cressida Bonas, who just so happen to be half-sisters.
While the blue-blooded beauties are officially out of the picture now, it seems that the young princes were once smitten with these ladies for a while so let's take a trip to an alternate reality and see who could have been the Duchesses of Cambridge and the Duchess of Sussex...
Nicknamed Bellie by her loved ones, blonde beauty Isabella Calthorpe is the daughter of Mary-Gaye Curzon and John Anstruther-Gough-Calthorpe and with that many surnames, you know she comes from a fancy background.
And when you have such a posh lineage, you're bound to have some well-to-do friends like the royal princes. Her younger brother Jacobi, who is Cressida's half brother, was one of the prince's polo pals and we'll get to Cressida herself later.
Prince William was quickly taken with the socialite and following his trial separation from Kate Middleton in 2004, royal biographer Katie Nicholl says the third in line to the throne began wooing the then-21 year old Isabella.
"While Kate was girl-next-door pretty, Isabella boasted cover-girl looks, a title and a stately pile to boot," Nicholl wrote in her book William and Harry.
"Sadly for William she had no aspirations to date a prince and despite his amorous advances declared that she was not interested."
A royal source told the Daily Mail in 2007, "He had fallen for her in a huge way and wanted to be with her. He propositioned her several times that summer and although Isabella was single, she knocked William back and said it would be too damaging for her and her career."
Duchess Catherine was reportedly so threatened by Isabella that she made her prince make a promise to her.
"It was obviously the break that William needed, and by Christmas they were back together again, although Kate had a condition. Word had reached her of William's visits to Isabella, and Kate insisted that William was not to contact her again," Nicholl wrote.
The Daily Mail's royal source shared a similar detail remarking, "William was madly in love with her but when he knew there was no chance of them getting together he went back to Kate."
"Kate was very aware of his obsession with Isabella and she was incredibly threatened by her. Isabella is drop-dead beautiful and would leave any girl in the shade. Kate accepted William back again but on the condition that he would not speak to Isabella again."
But things must have blown over as the blonde beauty was in attendance at Prince William and Duchess Catherine's royal wedding.
Now 38, Isabella has worked as an actress and model and went on to marry Richard Branson's son Sam in 2013 with whom she shares two children.
WATCH: Prince William and Kate Middleton exchange wedding vows. Post continues...
Before Meghan Markle came along, former bad boy Prince Harry dated a bevvy of beauties including the One Before The One, Cressida Bonas.
Isabella's younger half sister met the red-headed royal back in 2012 through close friend Princess Eugenie, Harry's paternal cousin and dated until 2014 but she was the one to break things off.
According to Nicholl in her book Harry: Life, Loss, and Love, Cressida watched Will, Kate and a tiny Prince George embark on their royal tour of Australia and New Zealand in 2014 and was "completely spooked" by the TV coverage.
Nicholl wrote, "There was no way she wanted that sort of attention and she told Harry so."
Harry, who was reportedly madly in love with Cressida apparently tried to convince her they could make it work, but Cressida's mind was made up.
"Harry suffered a real blow when she said, 'I can't do this.' I think she really broke his heart," Nicholl added.
It seemed like history was repeating itself, Harry's other long term girlfriend Chelsy Davy reportedly ended their on-off relationship for the same reasons and was similarly triggered by Will and Kate.
Cressida herself spoke out about what it was like to date someone as high profile as Prince Harry, especially as she was trying to forge her own career as an actor and model at the time.
"I think it's that thing of being pigeonholed. Especially in this country, I find that people are very quick to put you in a box or put you in a corner and think, 'Oh well, you're that, so you must be that.' It's incredibly frustrating, especially in the industry that I'm in. But you know, it is the way it is...It's making a stand and saying, 'Actually no, this is who I am, and this is what I want to do,'" she told BBC Radio 4.
Like her half-sister, Cressida is on such good terms with her royal ex that she even attended his wedding to Duchess Meghan in May last year and commented that her biggest dilemma of the day was which hat she would wear.
"The invitation clearly stated that guests must wear hats. Yikes. I opted for a minimal feathered number — and can only hope I got it right," she penned in a blog post for The Spectator.
30 year-old Cressida continues to act and model and has even found herself a new Harry, surveyor Harry Wentworth-Stanley. But it's clear her relationship with her half sister is a close one.
To celebrate Isabella's birthday back in March, Harry's ex shared a snap of herself and the birthday girl captioning it, "HaPpY BiRtHdAy to my darling big sister Bellie. What an inspiring person, wonderful sister and mother you are 💗💗💗."
And while Bellie's account is set to private, we have no doubt she would share the same sort of thing.
As fate would have it, William and Harry ended up with their respective wives but it's fun to image a parallel universe where there were royal princess sisters.