The Prime Minister wrote to the manager, calling on him to “bring it home”. “We are not just hoping or praying,” he wrote.
“We believe in you, Gareth, and your incredible squad.”
The England team will play Italy at Wembley on Sunday at 8pm.
“On behalf of the entire nation, good luck, have a great game – and bring it home!” Mr Johnson wrote.
In the letter the Prime Minister wrote that Gareth Southgate’s team had “already made history”.
“You have lifted the spirits of the whole country, and tomorrow we know you can lift that trophy too.”
Gareth Southgate’s team has been flooded with messages of support ahead of the final on Sunday.
The Queen presented the 1966 World Cup to the England team, unbeknownst that it will be the last time the team would reach a final in a major tournament for 55 years.
“55 years ago I was fortunate to present the World Cup to Bobby Moore and saw what it meant to the players, management and support staff to reach and win the final of a major international football tournament,” the monarch wrote.
“I want to send my congratulations and that of my family to you all on reaching the final of the European Championships, and send my good wishes for tomorrow with the hope that history will record not only your success but also the spirit, commitment and pride with which you have conducted yourselves.”