LONDON (Reuters) - Well-wishers gathering in London to celebrate the wedding of Prince William and Kate Middleton will be able to watch the ceremony on two giant screens in the city centre, the capitals mayor said on Thursday. Only 1,900 people from family and friends to foreign dignitaries, diplomats, soldiers and charity workers have invitations to watch the service inside Westminster Abbey on April 29. Outside, tens of thousands of people are expected to line the route of the couples wedding procession.