The Serie A giants share an arean in the Italian capital and will build a new complex to replace the existing ground that has seen plenty of memorable moments over the years.
The new venue will be called 'The Cathedral' and is inspired by Milan's cathedral — the Duomo di Milano.
It is designed by Populous, who have designed some of the most iconic sporting arenas around the world in recent years.
They had a hand in the designs for Wembley Stadium, the main stadiums for the Sydney 2000 and London 2012 Olympic Games, the Emirates Stadium and Tottenham Hotspur Stadium.
The San Siro will remain intact until at least 2026, where the stadium is set to host the opening ceremony for the 2026 Winter Olympics.
"The new San Siro will be the most beautiful stadium in the world for its strong identity and recognisability. An attractive arena, accessible and sustainable for the city of Milan that will facilitate the growth of the clubs and their global competitiveness," said Paolo Scaroni, President at AC Milan.
Alessandro Antonello, Corporate CEO at FC Internazionale, said: "The New Stadium of Milan will be in an extra-contemporary green area that can be lived all year round.
"The new district for sport and leisure and its 50,000sqm park will make San Siro the go-to neighbourhood for sport and entertainment."
No timeline has been given but the project is expected it to be finished by 2024 or 2025.
The stadium will be part of a new district dedicated to sport and leisure that will include extensive green space.