Announcement of the signing was delayed by a final round of negotiations between the clubs that resulted in Palace securing a clause that will entitle them to a 10 per cent sell on fee should the right back leave for more than £50 million in the future.
“Aaron is one of the best upcoming defenders in the Premier League,” Solskjaer said. “He has the right work ethic, talent and mentality to play for Manchester United and he fits exactly the type of player that we are looking to bring into the squad to help us improve and push on further.
“Aaron is a young, hungry player and eager to learn and that’s important at his age. I am delighted he has signed with us and we look forward to continuing his tremendous development so far."