Britain's Prince William (Front R) and his wife, Catherine, Duchess of Cambridge (front L) sit on Centre Court as spectators perform a Mexican Wave at the Wimbledon tennis championships in London, June 27, 2011. [Photo/Agencies]

WIMBLEDON, England - Andy Murray performed a majestic bow on Centre Court, then sheepishly apologized to his royal fans - Prince William and new bride Kate - for his sweaty, unkempt appearance.

The royal couple, who were married on April 29, watched from the front row of the Royal Box on Monday as the fourth-seeded Murray beat Richard Gasquet to reach the quarterfinals.

"If I'd known they were coming, I would have shaved," Murray said, smiling. "I was thinking to myself as I came off I was sweaty and very hairy. I said to them, 'I'm sorry, I'm a bit sweaty."'

Andy Murray of Britain bows to Catherine Duchess of Cambridge and Prince William in the Royal Box after defeating Richard Gasquet of France at the Wimbledon tennis championships in London, June 27, 2011. [Photo/Agencies]

At least Murray had a well-practiced bow ready. Last year, he was watched by the Queen on her first visit to the tournament in 33 years and bowed low with one arm bent behind his back and one in front.

The players weren't obliged to bow for William and Kate, but after shaking hands with Gasquet, Murray waved to three sides of the Centre Court crowd before turning to the Royal Box and repeating his very proper bow as the couple stood and applauded.

"I hadn't planned on doing it before," Murray said after beating Gasquet 7-6 (3), 6-3, 6-2. "When the Queen came to our match last year we were told she was coming and that we would bow when we went on and off the court.

"But today we weren't told anything, so it was just sort of off the cuff."

Murray said it was "very nice" to meet the couple, who he said told him: "Well done on the match. Asked me how it was out there. That was it. Wasn't a long conversation."

William and Kate later returned to Centre Court and saw Venus Williams and then Rafael Nadal in action. The couple even joined in the wave during Nadal's match.

The visit wasn't announced in advance and wasn't part of their official royal duties. The Duke and Duchess of Cambridge arrived at about 12:30 pm and were given a warm ovation by the Centre Court crowd when they took their seats in the Royal Box 25 minutes later.

In keeping with Wimbledon's all-white dress theme, Kate wore an off-white, knee-length dress with tiered layers and embroidered straps. William wore a blue suit on a warm day in London, with temperatures about 30 degrees C.

Security was noticeably tighter at the All England Club, and a police helicopter circled the grounds early on during the Royals' visit.

There seemed to be a royal theme at Wimbledon on Monday. Six-time Wimbledon champion Billie Jean King was sitting behind Prince William and Mervyn King, Governor of the Bank of England, was also on the invitation list.

Later in the day, there was a visit from hip-hop royalty as Jay-Z watched Nadal play Juan Martin del Potro. Jay-Z had been expected to visit with his wife Beyonce, but the pop singer failed to show after headlining the Glastonbury music festival in southwest England on Sunday.

St. James's Palace said Kate is a tennis fan and has been to Wimbledon "quite a number of times." William visited Wimbledon several times as a child with his mother, Princess Diana.

William and Kate will begin their first overseas state visit as a married couple in Ottawa, Canada, on Thursday.