Bellanova, 22, started in Milan's youth team but made his professional debut at French side Bordeaux. After spells at Atalanta and Pescara, he signed for Cagliari in 2021 and made 31 appearances last campaign.
Bellanova said, “It's difficult to find the right words because a dream that I've had since I was young – playing for my favourite team – is coming true," he said. I hope to repay the faith the Club has shown in me.
“It's always been a dream of mine. It was also a dream playing there as an opponent of Inter, as was the case last year. It was exciting, absolutely thrilling. I can't wait to take to the pitch in the Inter jersey.
“I'm certainly more of an attacking wing-back as opposed to a defensive one. I like to have the ball at my feet and run at my opponents, but I know that I can still improve a lot. However, there's time; I'm young and really want to improve."
Of his experiences so far, Bellanova said, “They've really helped me, first and foremost the negative ones. They allowed me to learn a lot. Now, I'm at a bigger Club and everything will be more difficult, but I'm eager to start."