The 21 year-old had reportedly been courted by Stoke City, but he has signed a three-and-a-half-year contract with the Premier League leader and will now spend the rest of the season in the Championship.

The England youth international, who first moved to the United States at the age of 14, is excited at the prospect of returning to his homeland.

"I can't wait to get started over here," he told Man City's official website. "I've really enjoyed my time with New York City and I'd like to thank [New York coach] Patrick Vieira and his coaching staff for helping me to develop as a player.

"I feel I've really improved working under him and playing regularly in the MLS, but now I'm looking forward to testing myself in England.

"Middlesbrough are a good club, with Premier League experience and they're in the mix for a return via the play-offs this season.

"Hopefully I can help them achieve that."

Harrison scored 14 goals in 59 games in his two seasons in New York and was called up to England's Under-21 squad in October, making his debut against Scotland at Boro's Riverside Stadium.