The leader and the chief executive of Staffordshire County Council have added their names to a world record attempt at the National Memorial Arboretum.
The Alrewas site are encouraging thousands of people to write on what it hopes will be the Christmas card with the largest ever number of signatures.
The current record is 21,000 and was set by Dubai Police in 2015.
Cllr Philip Atkins, leader of Staffordshire County Council, and chief executive John Henderson have added their names to the bid.
“Staffordshire has a strong historic connection with our armed forces, continuing with large bases in Stafford and Lichfield, and we are committed to supporting armed forces personnel wherever we can,” Cllr Atkins said.
“The signing of this card is just one way for us to show our commitment and appreciation for those risking their lives to serve their country.
“It would be wonderful if we could break the world record in the process, and show our armed forces that people in Staffordshire appreciate their sacrifices and thank them for keeping us safe.”
The card will soon embark on a tour of the Midlands and London before being presented to senior military figures and going on display at the Ministry of Defence in Whitehall.
Sarah Montgomery, managing director of the National Memorial Arboretum, said: “We thought the giant Christmas card would be a wonderful way in which to pay tribute to the Armed Forces at this special time of year.
“It will be quite a task to break the existing world record for the number of signatures on a greetings card, let alone attempt to go even further by filling all the 20,993 spaces on our card.
“However, we’ve got off to a great start and we are confident that thousands of people of all ages and from all walks of life will support us in meeting this tough challenge.”