The crowd capacity at Wembley will be raised to more than 60,000 for the semi-finals and final of Euro 2020, says the UK government.
It means the stadium will be at 75% capacity for the games.
The increase will also see the largest crowds assembled for a sporting event in the UK in more than 15 months.
"It is great news that so many fans will be able to watch the final three matches of Euro 2020 at Wembley," said Uefa president Aleksander Ceferin.
The UK government has postponed lifting all restrictions until 19 July but the game at Wembley, along with certain other sporting events, is being allowed extra crowd capacity under its Events Research Programme.
Wembley's capacity has been reduced to 22,500 for group fixtures at Euro 2020, but that is set to be expanded to 45,000 - around 50% of full capacity - for two knockout games in the last 16 before the semi-finals on 6 and 7 July and final on 11 July.
