The 23-year-old winger only has 18 months left on the contract he penned when he joined the Serie A club in 2019, and will consider committing to a fresh deal.
However, he also made it clear that he is currently focusing on Portugal's World Cup campaign, as they have already secured a ticket to the knockout stage.
"I'm happy, proud, now I have to concentrate on the World Cup, then I will talk to Milan as soon as I arrive," he told La Gazzetta dello Sport.
"Do I want to sign the contract? Even before arriving in the national team we had a meeting with Maldini, it was positive, so when I arrive in Milan we will talk."
Leao has made 28 appearances for the Rossoneri so far this season, scoring eight goals and providing 10 assists.