Fletcher was a boyhood Celtic fan but decided against joining Parkhead in favour of bitter rivals Rangers. But the Ibrox club were pipped at the post by The Red Devils.
The Scottish international says that Sir Alex Ferguson was the deciding factor in him joining United, as he decided against joining Dick Advocaat at Rangers.
"I was spotted by United when I was playing for Celtic Boys Club when I was about 12 and I started coming down during school holidays," said Fletcher.
"I kept doing that until I signed for the club on my 16th birthday. The manager had a big involvement in me coming here.
"Every time I came down he went out of his way to make sure my family and I felt welcome. That was brilliant."
Although neither of the Scottish giants could compete with the set-up at Old Trafford, Fletcher says the youth development at Rangers was better, and that prompted his decision.
"I grew up going to Celtic with my uncle who had a box at Celtic Park.
"He bought me a season ticket one year and I went along for two or three seasons.
"I had the opportunity to join Celtic but Rangers had a good youth set-up and track record of bringing through players, so I thought that was the best place to be.
"At Celtic that wasn't happening."