Wedding Bells for Wills & Kate?

If the old adage "the couple that plays together stays together" is to be believed, then Prince William and Kate Middleton are a solid bet for the future. The lovebirds are often seen partying with friends as well as attending concerts and sporting events, and it's this kind of foundation that leads many royal experts to believe that William and Kate will announce their engagement next spring.

William has an unusually large gap in his July schedule next year — after he completes his military training — which has sparked talk of a summer wedding.

On June 7, the pair attended a charity boxing night, where some of their pals went toe-to-toe to raise money for the Starlight charity, which helps terminally and seriously ill children.

William, who turns 26 on June 21, cheered on his buddy James "The Badger" Meade by chanting "Badger! Badger!" while Kate, 26 — wearing a stunning, pale-pink Issa dress — winced as the blows landed.

William's brother, Prince Harry, 23, and his long-term girlfriend, Chelsy Davy, 22, were also ringside at the Royal Lancaster Hotel in London. Kate and William later enjoyed the party (where tickets cost $200), dancing and knocking back vodka shots till 4 a.m.

"It would be astonishing now if they did not get married," a royal insider tells OK!. "They could announce their engagement later this year. Royal engagements are usually short, and the most likely dates are a February 2009 engagement for a summer 2009 wedding."

The only stumbling block that might stand in the way of William marrying his girl could be the queen's concerns about Kate's career — or a perceived lack thereof.

A British newspaper reported that the queen had allegedly told close friends that she was unsure what Kate, a former accessories buyer for fashion chain Jigsaw, actually did for a living. Other reports, however, claim that the queen is a huge fan of Kate and has enjoyed talking to her in the past.

After Kate weds William, she'll officially be known as Princess William of Wales, a title that doesn't quite roll off the tongue.

"It might sound strange at first," says Charles Kidd, editor of Debrett's Peerage and Baronetage, which details Britain's titled families, "but I'm sure the public will soon get used to it."