Middlesbrough have officially completed the signing of Sunderland’s Paddy McNair.

The former Manchester United defender signs for the Boro for a reported fee of around £5million, although the club has refused to disclose the actual amount.

The club have beaten off Premier League competition and the highly-rated 23-year-old midfielder, who can also play in defence, joins on a four-year contract.

McNair becomes Boro’s first signing of the summer under Tony Pulis, supposedly coming in to replace Mo Besic whose loan spell expired at the end of the season.

The Northern Irishman has made 20 caps for his country, as well as 50 appearances for both Manchester United and Sunderland.

The versatile 23-year-old enjoyed a brilliant return from injury to end last season, with a string of impressive performances which saw him score four goals in his last five games for Sunderland.

The club said on their official website:

“The player’s arrival will add increased competition for places in the team for next season.

“Due to the terms of the deal, the fee will remain undisclosed.”