Manchester United defender Paddy McNair has left the club to join Sunderland on a four-year deal, the club announced on their official website.
The 21-year-old struggled to enjoy regular first-team football at Old Trafford and will now work under former United boss David Moyes at the Stadium of Light.
Moyes says the youngster will be deployed in a midfield position this season.
"Paddy is young, athletic and is improving all the time and he's got experience playing for Manchester United," he told Sunderland's official website.
"I've had a look through history and some of the best boys to come here over the years have been from Manchester United; even if you look at how well John O'Shea and Wes Brown have done and then back to people who have been on loan like Danny Welbeck and many more.
"I see Paddy as more of a midfield player at the moment – he played with Northern Ireland as a midfield player – and he can also do two or three jobs.
"We may need to use him in some other positions at the moment while we are aiming to add to our squad, but we want to give him a bit of time to settle in."