Chelsea have agreed a deal to sign Borussia Dortmund midfielder Christian Pulisic.
The United States international will remain at the German club on loan for the remainder of the season before completing his move to Stamford Bridge in the summer.
Chelsea will pay £57.7million for Pulisic, who has scored three goals in all competitions so far this campaign.
His contract with Dortmund was due to expire in 18 months and the 20-year-old has always had ambitions of playing in England.
"It was always Christian's dream to play in the Premier League," Dortmund's sporting director Michael Zorc told the club's official website.
"That certainly has to do with his American background and as a result we were unable to extend his contract. Because of this, we have decided to accept an extremely lucrative bid by Chelsea, given the low contract security.
"Christian Pulisic is a perfect player. I am sure that in the coming months he will do everything in his power to bring his high quality to the team and to achieve his sporting goals with his team-mates Borussia Dortmund.
Pulisic, who joined Dortmund as a youth player in 2015 and has made over 100 appearances for the club, could arrive at Stamford Bridge as a title winner with Dortmund currently leading the Bundesliga by six points.
Chelsea director Marina Granovskaia told the club's official website: "We look forward to welcoming him to Stamford Bridge in the summer and wish him and Dortmund every success for the remainder of the season.
"We are delighted to have signed one of Europe's most sought-after young players."Christian has shown his quality during a fantastic spell in Germany and at just 20, we believe he has the potential to become an important Chelsea player for many years to come."
Pulisic will become Chelsea's third most-expensive signing in their history after the £71million deal for goalkeeper Kepa Arrizabalaga and £60million they spent on striker Alvaro Morata.
"It's a privilege to have signed for such a legendary club and I look forward to working hard towards being a contributor to their team of world class players," said Pulisic.
Pulisic's arrival could spark fresh fears over the future of star man Eden Hazard as he continues to mull over his long-term future at Chelsea amid interest from LaLiga heavyweights Real Madrid.