LONDON — The wedding of Prince William and Kate Middleton was watched by 26.3 million viewers in the U.K. and a livestream audience of 72 million on YouTube in 2011.

The bride wore a wedding dress designed by Sarah Burton from Alexander McQueen, with an ivory lace bodice and flowing satin skirt and train. The designer also created the bridesmaid dress for Middleton’s sister, Pippa Middleton — a form-fitting cowl neckline dress.

The dress cemented Burton as a household name and started a relationship with the royal household where McQueen became a fixture for important royal occasions, from Trooping the Colour to the funeral of Queen Elizabeth II.

The departure of Burton from McQueen has raised many questions about the future relationship between the new Princess of Wales and the British designer.

Will they continue to work together? Is this a new chapter for them both? And do the two entities even need each other?

“I can’t imagine that this is the end of the line for Kate’s relationship with Sarah. They appear to have become true collaborators and it’s clear that the princess seeks Sarah’s advice and trusts her implicitly. We saw evidence of this when Sarah helped organize a really beautiful photo shoot to mark Kate’s 40th birthday, enlisting one of her favorite photographers, Paolo Roversi,” said Bethan Holt, author of “The Queen: 70 Years of Majestic Style” and “The Duchess of Cambridge: A Decade of Modern Royal Style.”

In Prince Harry’s memoir “Spare,” it is revealed that Middleton relied on the advice of Burton about Princess Charlotte’s bridesmaid’s dress for the wedding of Harry and Meghan Markle.

Bethan adds that she would love to “see Sarah designing for the princess privately or under her own name label, continuing to deliver the kind of beautifully crafted gowns and sleek tailoring she’s come to provide at McQueen.”

The relationship between Middleton and Burton is a unique one and the closest the royal household has come in contact with high Fashion since Princess Diana entered the firm.

Diana wove herself into the fantasy of clothes by wearing Catherine Walker, Bellville Sassoon, Donald Campbell, The Emanuels and Bruce Oldfield while she was still part of the royal family. Meanwhile, Middleton is firm in her stance; she wears a specific roster of designers such as McQueen, Jenny Packham, Erdem, Catherine Walker and Emilia Wickstead.

She’s never seen to take Fashion too seriously, but is always respectful and considerate of the wider British Fashion industry by wearing pieces from high street and luxury houses, which Holt said gives the princess a “relatability and modernity.”

“The princess holds a unique economic power to promote designers and brands, particularly on behalf of the British Fashion industry. No other Fashion, not even that of celebrities, is so closely tracked, reported, and shopped,” said Elizabeth Holmes, author of “HRH: So Many Thoughts on Royal Style.”

“Kate’s style at that time was criticized as part of the broader narrative taking aim at her commoner status. Choosing a high-Fashion brand with an edgy reputation and a willingness to lean into drama turned more than a few heads,” she added.

When Burton designed the wedding dress for the princess, it hushed critics who had questioned her ability to continue the legacy of the brand.

The exit of the designer has also raised the question of whether Burton will become Middleton’s full-time dresser, a role similar to which Angela Kelly, Queen Elizabeth’s dresser up until her death, had.

“There may reach a point where Catherine prefers to wear only bespoke pieces, like Angela Kelly’s designs for the queen, but I don’t think we are there yet, nor will we be in the near future,” said Holmes.

Holt explained that during the Diana years, many designers spoke about how difficult it was to fulfill the needs of the Princess of Wales alongside other commercial aspects of their companies.

“So having someone without those demands could be very beneficial,” she added.

In the long run, Burton has helped Middleton get out of her comfort zone and in return, the designer has become an instrumental part of shaping the future queen’s style.