Britain's Foreign Office said royal officials had sent their regrets to Estibalis Chavez, a 19-year-old fan who has protested outside the country's embassy in Mexico City for 10 days demanding an invite.

In this photo taken Wednesday Feb. 16, 2011 at Buckingham Palace in London, a member of the Lord Chamberlain's Office, no name given, places invitations into envelopes, to the wedding of Prince William and Kate Middleton, before posting them to the lucky guests who will be present at the April 29, 2011 royal wedding to be held in Westminster Abbey. Almost 2,000 guests have been invited to the wedding of Prince William and Kate Middleton. Their names have not been released but the Westminster Abbey congregation is expected to feature celebrities, leading politicians, heads of state and royalty from across the world. [Xinhua]

At Westminster Abbey, Prime Minister David Cameron and his deputy Nick Clegg will likely be among 200 lawmakers, government staff and diplomats invited - with high-profile ambassadors also expected to attend.

Leaders of several Commonwealth nations - and the governor-generals who represent the queen in Canada, Australia and New Zealand - are also thought certain to be included among the guests.

Vickers said many European royals likely to attend are closer in age to William, second in line to the throne, than his father Charles - suggesting the guest list may have a more youthful feel than royal weddings of the past.

William's office said about 1,000 guests will be the family and friends of the prince, his bride and their parents. Roommates who lived with William and Middleton as they studied at Scotland's St. Andrews University, young entrepreneur Guy Pelly and television reporter Tom Bradby - who conducted the only interview with the couple following their engagement - could all receive an invitation.

Around 80 guests will come from charities which William supports, including African wildlife charity Tusk, and Centrepoint, which helps young homeless people.

Thirty members of the armed forces, likely to be William's colleagues from his Royal Air Force search-and-rescue unit, will also attend.