Prince William and Kate Middleton will announce their engagement next spring, Royal experts believe.

Prince William and Kate Middleton to announce their engagement next spring?

William has a gap in his July schedule next year — after he completes his military training — which has sparked talk of a summer wedding, OK reports.

"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."

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