Kate Middleton blows kiss during emotional Wimbledon appearance

The Duke and Duchess of Cambridge showed some rare emotion in public as they made a surprise move at Wimbledon.

The Duchess of Cambridge blew a loving kiss to her parents Carole and Michael Middleton as they took to their seats in the Royal Box at Wimbledon this morning (AEST).

Kate Middleton, 40, and Prince William, who were also greeted by comedian and author David Walliams, looked in high spirits as they watched Wimbledon holder Novak Djokovic take on Jannik Sinner on Centre Court.

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During the most nail-biting moments of the game, avid tennis fan Kate could barely watch as she was seen covering her eyes and clasping her hands in front of her mouth, The Sun reports.

Prince William was also spotted putting on a very animated display and clenching his teeth during a tense serve, before erupting into laughter alongside his wife.

Kate Middleton spots her mum Carole in the crowd. Picture: Stephen Lock / i-Images / Media Mode

They enjoyed the show. Photo by Glyn KIRK / AFP.

In a surprise move, the royal couple then snuck over to Court No. 1 — away from the Royal Box — to soak in the epic five-set battle that saw Britain’s Cameron Norrie reach the semi-final in crazy scenes.

The Duchess of Cambridge arrived on Court No. 1, alongside Tim Henman, during the third set, having witnessed Djokovic’s comeback victory over Jannik Sinner — and her husband arrived in the fourth just as Norrie was turning the match around.

His victory sees him become only the fourth British man to reach a Wimbledon singles semi-final in the open era.

The royals were seen in some photos letting their emotions go as they screamed in support of Norrie.

David Walliams and Catherine, Duchess of Cambridge in the Royal Box. Photo by Julian Finney/Getty Images)

Earlier, the Duke and Duchess were spotted waving to fans as they crossed the bridge from the millennium building into Centre Court after entering at the SW19 grounds via the players’ entrance.

Looking typically chic, thrifty Kate put on an elegant display in a recycled $2500 Alessandra Richnblue polka dot midi dress, which she first wore at a local street party to celebrate the Queen’s Platinum jubilee.

The mum-of-three completed her ensemble with a pair of slingback white heeled sandals from the same designer and co-ordinating Mulberry handbag.

Catherine, Duchess of Cambridge and Prince William. Photo by Julian Finney/Getty Images.

Wearing her long brown locks loose, Kate, who accessorised with a pair of dainty pearl-drop earrings, kept her make-up natural - adding just a touch of blusher and a pink lip.Meanwhile, Prince William looked dapper in a light grey check suit which he paired with a navy tie and matching smart trousers.

Kate — who is patron of the Lawn Tennis Association - is a regular fixture at Wimbledon.

United Kingdom loses it over newest superstar

Now Cameron Norrie really is a true British tennis hero — because he’s put the nation through the wringer in traditionally agonising fashion.

Like Andy Murray or Tim Henman in their pomp, Norrie won a nerve-shredding, topsy-turvy Wimbledon marathon against David Goffin to reach his first Grand Slam semi-final, against Novak Djokovic on Friday.

Cameron Norrie of Great Britain celebrates winning against David Goffin. Photo by Justin Setterfield/Getty Images.

Spectators watch the big screens from The Hill during the Men's Singles Quarter Final match showcasing Cameron Norrie of Great Britain. Photo by Ryan Pierse/Getty Images.

The match lasted three-and-a-half hours, five sets, and contained two senior Cabinet resignations in the middle of it, as Norrie twice clawed his way back from a set-down to clinch the most significant win of his life, with a 3-6 7-5 2-6 6-3 7-5 scoreline.

Norrie, 26, said: “I’m so happy to get through. It wasn’t going my way, I wasn’t feeling good, David was playing really good but thanks to the crowd, I managed to stay as patient as I could. It was all just adrenaline.

“Winning a match like this gives me flashbacks to all the hard work and all the sacrifices I’ve had to make - it has definitely paid off.

“It only gets tougher now - I’m going to enjoy the semi-final.”

Norrie is seeded ninth but had never previously reached the fourth round of a Major, or been properly lauded by his adopted nation until this Wimbledon.

— This story originally appeared on thesun.co.uk and has been republished with permission