Prince William and Catherine, duchess of Cambridge, can't be called stiff -- at least not when they're watching a Wimbledon tennis match live. 

The second in line to the British throne and his wife sat in the Royal Box on center court Tuesday to take in the match between Bulgaria's Grigor Dimitrov and Britain's Andy Murray, and the intensity of the event was written all over their faces. 

The royals' disappointment was pretty obvious when Dimitrov defeated Murray in the men's singles quarterfinal match. Prince George's parents often get passionate at sporting events and this time was no different, save for the proper ensembles they wore: a suit for Wills and a demure eyelet dress by Zimmerman for Kate.

The couple also took in the women's singles quarterfinal match where Simona Halep of Romania defeated Germany's Sabine Lisicki.

The duchess was photographed smiling, grimacing and biting her lip, and Wills was seen burying his face in his hands during one upsetting maneuver. (Royals: They're just like us!)

On Monday, the former Kate Middleton visited a the M-PACT Plus counseling center at the Blessed Sacrament School in London and, not surprisingly, her wardrobe made more headlines than her charity work. The Goat Scarlett belted shift dress she wore sold out online shortly after she was photographed in it, according to All the Rage.

In other Kate fashion news: Madame Tussauds in London relaunched its wax figures of the Cambridges, decking them out in evening wear -- specifically a teal Issa London gown and a Gieves and Hawkes suit -- rather than the iconic engagement ensembles that the likenesses donned when they debuted in 2012. 

Even in wax, Kate can work that dress. Follow me @NardineSaad.