He told manutd.com: "When I was at Aberdeen I turned down a few offers but when the opportunity came to join Manchester United I couldn't say no.
"I admit Sir Matt Busby was a factor in my decision… when I was a kid I once went to see United play just because I knew Sir Matt would be there. His reputation in Scotland was massive and only enhanced by what he'd done at Old Trafford. He was very welcoming and he genuinely wanted me to do well. I used to really enjoy the chats we used to have. I always remember the advice he gave me about the papers: he told me not to read them!"