Britain's Prince William (R) and his fiancee Kate Middleton arrive at The Thursford Collection in Norfolk, England, Dec 18, 2010. [Photo/Agencies]

LONDON - The invites haven't been sent yet - but some European royals seem to have been given a quiet tap on the shoulder.

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The crown prince of Serbia and ex-King Michael of Romania say they're among the hundreds of privileged guests expected at the wedding of Prince William and Kate Middleton in London on April 29.

Formal invitations to the widely anticipated event aren't expected to go out until later. But Michael, a first cousin of William's grandfather, Prince Philip, will be among those attending, his office confirmed to The Associated Press Tuesday.

Crown Prince Alexander of Serbia says on his website that he too had been invited.

A royal spokeswoman declined to comment on the guest list, which is still being finalized.