Reason why Kate Middleton was allowed to break strict Royal Box Wimbledon rule

Kate Middleton looked effortlessly elegant as she returned to Wimbledon over the weekend.

But alongside her outfit, some royal fans may have noticed she'd worn something that's usually discouraged in the Royal Box.

The Princess of Wales, 44, who attended both the women’s and men’s singles finals, was spotted wearing an olive-green, wide-brimmed hat while watching the action unfold from the prestigious Royal Box.

Kate Middleton was spotted in the Royal Box at Wimbledon over the weekend. (Tim Clayton/Getty Images)

Observant royal fans may have been left wondering how she'd managed to get away with breaking one of the venue's best-known pieces of etiquette.

In case you missed it, guests sitting in the Royal Box at Wimbledon are typically discouraged from wearing hats because they can block the view of spectators sitting behind them.

The Royal Box has long had a strict dress code, with women traditionally asked to avoid headwear for exactly that reason.

But there was one important detail this year that allowed Catherine to break the fashion rule.

Thanks to the soaring temperatures over the weekend, Wimbledon temporarily eased its usual dress-code guidance for Royal Box guests.

As sweltering heatwaves persist across the UK and Europe, Kate and her fellow spectators were able to wear their hats while watching play to stay protected from the sun.

Princess Charlotte and Prince George joined their parents at the Wimbledon men's singles final (Tim Clayton/Getty Images)

In fact, Wimbledon even handed out official hats to some Royal Box guests to help them cope with the heat, including Prince George and Princess Charlotte, who joined their mum and Prince William for the men's final.

Any strict dress-code followers can rest assured that Kate removed her hat when she stepped onto Centre Court to present the winners' trophies.

Avid Royal watchers may recall that this isn't the first time Kate's Wimbledon headwear has sparked conversation.

Last year, fans questioned why she appeared to bend the same Royal Box etiquette, but the guidance around hats at the tennis tournament has always been more flexible when weather conditions call for it.

Guests of the Royal Box who didn't get the hat memo were treated to flashy fedoras provided by Wimbledon to shield their faces from the sun.

Alongside the Princess of Wales and her family, other famous faces seen at the finals included singer Jennifer Lopez - who also caught some flack for her wide-brimmed hat -, Oscar winners Nicole Kidman, Dustin Hoffman, and Rami Malek, actor and director Ben Stiller, and fashion mogul Anna Wintour.

Also spotted amongst the spectators were A-listers like Andrew Garfield, Theo James, Lily Collins, Daisy Edgar-Jones, Cynthia Erivo, and Liam Hemsworth - to name but a few!