As Andy Murray crashed out of the Wimbledon quarter finals the Duke and Duchess of Cambridge were left despondent.
Looking on from the Royal Box, William blew out his cheeks and Kate clapped as Murray waved to the crowd.
Murray was beaten by Grigor Dimitrov in the quarter-final clash played out in warm, sunny conditions.
Dimitrov beat Murray 6-1, 7-6, 6-2 to reach his first ever grand slam semi-final.
Andy Murray has crashed out of his Wimbledon quarter-final clash with Grigor Dimitrov.
Dimitrov beat the Scot 6-1, 7-6, 6-2 to reach his first ever grand slam semi-final.
The Duke and Duchess of Cambridge cheered on Andy Murray during his Wimbledon quarter-final clash with Grigor Dimitrov today.
Kate paid homage to the All England Club's strict fashion rules for players by wearing a white dress by Australian brand Zimmermann.
William and Kate were joined in the Royal Box by Princess Beatrice, comedian Michael McIntyre and England rugby union coach Stuart Lancaster on a sunny, warm day at SW19 where the temperature was due to reach 22C (71.6F).
Murray lost the first set to his Bulgarian opponent.
Nick Kyrgios produced one of the greatest shocks in Wimbledon history when he beat Rafael Nadal today - but who is the 19-year-old?Read the full story ›
Serena Williams says she is "heartbroken" at having to withdraw from Wimbledon because of a viral illness.
The American was forced to forfeit her doubles match with sister Venus at the All-England club after becoming unwell on court.
The 32-year-old was knocked out of the singles in the third round last week.
"I am heartbroken I'm not able to continue in the tournament. I thought I could rally this morning, because I really wanted to compete, but this bug just got the best of me. I want to thank my sister, Kristina, Stefanie and our teams for their support," the five-time champion said in a statement.
"We were all looking forward to a great match. From the bottom of my heart, I thank all of the fans for their cheers and understanding. I look forward to returning to Wimbledon next year."
Venus Williams added: "Unfortunately Serena has been feeling unwell for the past few days and she just couldn't play to her potential today. I'm really proud of her for trying because we just love playing doubles together. We are looking forward to coming back to Wimbledon next year."
World number one Rafael Nadal has been knocked out of Wimbledon after a shock defeat to Australian Nick Kyrgios.
The 19-year-old, who is ranked 144th in the world and making his Wimbledon debut, beat the Spaniard 7-6 5-7 7-6 6-3 on Centre Court to condemn the two-time champion to a fourth-round exit.
Kyrgios will now play Canada's Milos Raonic in the quarter-finals.
Serena Williams was forced to withdraw from her doubles match as a result of a viral illness, Wimbledon organisers said.
The 32-year-old appeared groggy as she served four consecutive double faults on Court One, as the sisters forfeited the game in the first set.
"The word from the referee's office is that Serena Williams is suffering from a viral illness," a Wimbledon tweet said.
Serena Williams was forced to pull out of her doubles match with sister Venus at Wimbledon after she became unwell on court.
In scenes which were often uncomfortable to watch, the American appeared dizzy on court and was unable to hit or bounce the ball.
After she served four consecutive double faults, umpire Kader Nouni came down to speak to the sisters as the worrying situation continued.
The sisters eventually forfeited the match against German Kristina Barrois and Swiss Stefanie Voegele after going 3-0 down in the first set.
The commentator said Williams, who has won five Wimbledon singles titles, was a "shadow of herself" and appeared to be "sleepwalking" through the match.
Singers Katherine Jenkins, Cliff Richard and Elaine Paige were spotted enjoying the action on day nine of the Wimbledon Championships.
Judy Murray has praised her son's decision to hire a female coach as she warned there were not enough young girls playing tennis.
On Andy Murray's decision to appoint former Wimbledon champion Amelie Mauresmo as his coach, Judy said: "It certainly raised awareness and became a huge talking point.
"It definitely shows that if you have the skills, the knowledge and there is a personality fit, there is absolutely no reason why women can't coach at the top end of any sport."
The captain of Britain's Fed Cup side - the international team competition for women tennis stars - also revealed her fears about the lack of young girls playing tennis.
She said: "The things that are trendy for kids to play with nowadays tend to be sedentary things, you sit and twiddle your thumbs or you watch something on a wide screen and that is just a fact of life."