Young Belgium striker Charles De Ketelaere was due to complete his transfer to AC Milan from Brugge on Tuesday, Italian media reported.
The 21-year-old, who has eight Belgium caps, arrived in Milan on Monday night and was greeted by a few fans.
He began his medical in the morning ahead of signing his contract with the Serie A champions.
De Ketelaere tweeted a tribute to home-town club Brugge, which he joined at the age of seven, on Twitter.
"I want to thank Club Bruges for giving me the opportunity since I was a child to belong to their ranks, for making my dreams come true, for having trained me as a professional player," he wrote on Monday evening.
AC Milan reportedly offered 35 million euros ($36 million) including bonuses.
He is Milan's third signing of the summer following another Belgian striker, Divock Origi from Liverpool and French midfielder Yacine Adli from Bordeaux.
But the Serie A champions have lost defensive midfielder Franck Kessie to Barcelona and central defender Alessio Romagnoli to Lazio.
AC Milan will open their title defence on 13 August at home to Udinese.