Newcastle United have signed England midfielder Jonjo Shelvey from Premier League relegation rivals Swansea City for £12m.
The 23-year-old passed a medical at St James' Park before completing a five-and-a-half-year deal on Tuesday.
"I'm so glad that it's finally done," said the former Liverpool player.
"I drove up through the night to be here so it's been a manic 24 hours, but it's all been worth it to come here and play for this great club."
Newcastle head coach, Steve McClaren said he had admired Shelvey for some time, adding: "He has great experience for a young English central midfielder."
Capped six times by England, he becomes Newcastle's second January signing after Senegal midfielder Henri Saivet's arrival on Monday.
The 25-year-old, who played in the 2015 Africa Cup of Nations, joined from Bordeaux on a five-and-a-half-year deal for an undisclosed fee after helping the French club win Ligue 1 in 2009.
Shelvey, who signed a four-year contract extension with Swansea in 2015, is the first player to leave since Alan Curtis took charge.
The former Charlton player arrived at the Liberty Stadium in July 2013 from Liverpool - who will receive about £500,000 because of a sell-on clause - for an initial fee of £5m.
He helped the Swans to their highest Premier League finish of eighth in the 2014-15 season, but his performances this season frustrated many fans.
He has started just three Premier League games since October and was not part of the squad for recent matches against Leicester, Manchester City and Manchester United.
His final appearance in a Swansea shirt came in the FA Cup third round defeat at Oxford United.
Newcastle occupy the final Premier League relegation spot with the Swans two points and one place above them in 17th.
Reaction - 'It is a lot of money'
Former Newcastle and England winger Chris Waddle: "I'm surprised they've let him go to a rival team in that position but it's good money and they're making a profit. To ex-players like myself it's a lot of money.
"On his day he is very talented but whatever has happened at Swansea, he seems to have gone off the boil and become very inconsistent.
"He's still young and you would expect a lot more to come from Jonjo Shelvey. This move might freshen him up."
Ex-Swansea City winger Leighton James told BBC Wales Sport: "That's good business for a player who doesn't give me the impression that his heart and soul is in Swansea.
"He's a one-in-five, one-in-six player - a bit like his passing. For me he hits one great 40-yard pass and then the next four or five times gives the ball away.
"He's not the kind of player I'd want to see battling in a relegation fight."
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