Last year Gianluigi Donnarumma bought himself on a video game for 5 million euros. Now, days before his 18th birthday, the Milan goalkeeper would probably command a fee of at least four times that sum in real life.

Sixteen months is a long time in football. When Donnarumma made his debut on Oct. 25, 2015, few would have known who he was. Nearly 60 club matches and two Italy appearances later, the teenager is a household name.

Donnarumma was just 16 years, 8 months when he was given his debut for Milan by then-coach Sinisa Mihajlovic, helping to beat Sassuolo 2-1.

"The night before Milan-Sassuolo we were at the training ground and Mihajlovic took me aside and asked me if I felt ready," Donnarumma said. "I was speechless, I didn't expect it, but he knew very well that he could count on me."

On Sunday, the day after his 18th birthday, the goalkeeper will celebrate his 60th appearance for Milan, again against Sassuolo.

He is considered the heir to Italy's longtime goalkeeper and captain Gianluigi Buffon.

Donnarumma became the youngest 'keeper to play for Italy, and the youngest player overall in modern times when he replaced Buffon at halftime of a friendly against France on Sept. 1, conceding one in a 3-1 defeat.

He kept a clean sheet in his second Italy appearance, when he also replaced Buffon at halftime during a friendly against Germany at San Siro, where he plays his club football.

Donnarumma's youth was brought starkly into light in a tender moment when he arrived at the Italy training camp for the first time, and was dropped off by his parents like a child on his first day of school.

"Buffon is special," Donnarumma said. "I've got to know a splendid person in the national team. He really helps me a lot. The whole group is great. I was nervous when I first got called up, (but) I was really welcomed. Right from the first night everyone was joking with me.

"I hope to still be on the pitch when I'm Buffon's age (38). Hopefully with the Milan shirt. Playing for the Rossoneri was a dream. Now that I've realized it, I hope to also become captain. Maybe in 10 years though, there are others who deserve it more."

There are reports Juventus want him to become Buffon's heir in Turin, but Donnarumma — a lifelong Milan fan despite being born near Naples — has firm loyalties.

"I'm a regular in the team I support with all my heart," he said. "It doesn't get any better."

His brother Antonio, who is also a goalkeeper, believes his younger brother "would not leave Milan for anything in the world."

The love is reciprocated. Donnarumma's Milan shirts are sold the most.

His contract runs to 2018. As soon as he turns 18 he can sign a new five-year deal rather than the three-year ones underage players are limited to.

One of the first things the incoming new owners are expected to do, once they complete the purchase of Milan on March 3, is to call Donnarumma's agent, Mino Raiola.

"My agent is thinking about the contract and I am sure there will not be any problems," Donnarumma said. "I'm thinking more about my driving license than my contract renewal.

"I have to be driven to training but at least I always choose the music to listen to. Usually Neapolitan songs. And it doesn't matter if the others in the group don't like them and immediately put on their headphones so as not to hear."

A new contract is expected to increase his salary from 200,000 euros a year to around five million. Not bad at 18. Those who know him don't expect the money or increasing fame to go to his head.

"Life has completely changed and I'm very happy about it," Donnarumma said. "School has just become a little bit harder than it used to be.

"I have made a lot of sacrifices because I want to arrive at the top. And I have not arrived yet. I have not done anything yet. Every training session is a chance to improve."