Martin Wood, who at 7ft 2ins is the tallest town crier in the world, will be taking on a central role in next week's birthday celebrations at the palace.
Mr Wood, who was also selected to take part in the Queen Mother's 100th birthday celebrations, will join 19 other town criers for the occasion.
The ceremony will see him leading his fellow criers in three cheers for The Queen, as part of the Royal Proclamation, before a parchment scroll is presented to the Queen's officers.
Mr Wood said he was honoured to have been selected for the role.
He said: "I am very proud. It is a great honour. It was a great honour to be invited to go to London in any case but an even greater honour to be asked to take part in the proclamation itself.
"It is something which traditionally, way back when, was the duty of the town crier to make any royal announcement so we are just carrying on a tradition that is 1,000 years old. It will be great to be there and flying the flag for Shrewsbury as well."
Mr Wood explained that his role would entail leading his fellow town criers in the cheers for the Queen.
He said: "There will be about 20 town criers who have been given permission to go town to London on the Thursday, April 21, to do a royal proclamation outside the gates of Buckingham Palace and then present a parchment scroll to one of the Queen's officers."
As part of the celebrations for her 90th birthday the Queen will light a beacon at Windsor, the first of more than 1,000 that will be lit across the country.