Amad Diallo shared a photo of his flight to Rome on Sunday as the Atalanta teenager prepared to officially become a Manchester United player.
Diallo, 18, agreed to a move to Old Trafford worth up to £37 million ($48m) over the summer.
But the clubs agreed to keep the youngster in Italian football until he was granted a work permit in the United Kingdom.
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The Ivorian has since received an Italian passport and, as United boss Ole Gunnar Solskjaer revealed, has cleared the last legal obstacles preventing him becoming a United player.