Ilkay Gundogan has become Pep Guardiola's first Manchester City signing, in a £21m deal from Borussia Dortmund.
Gundogan has agreed a four-year deal with the Premier League club.
"It feels amazing to be a Manchester City player," he said. "It is a new chapter in my life so I am very happy that it's sorted. I'm looking forward to a new challenge and I'm very happy.
"I have to thank Pep Guardiola who I spoke to a lot about this move and also Ferran Soriano and Txiki Begiristain who I had intense conversations with. From the first moment I was sure it was the right thing for me.
"To play in the Premier League and to play for one of the best teams in the Premier League is a big challenge. I am very happy to join the Manchester City family."
City's director of football Txiki Begiristain added: "Ilkay is an intelligent and versatile midfielder who can operate in a number of different roles. I think our supporters will enjoy his work ethic and technical ability and I believe he will be a very important player for us in the coming years."
The central midfielder is currently out injured with a dislocated kneecap, which has ruled him out of Germany's Euro 2016 campaign and could see him sidelined for a further five months.
Gundogan, 25, has been a key player for Dortmund during his five years at the club, in which he has won a Bundesliga title and three German Cups, and reached the final of the Champions League.
He made 157 appearances during his time at Dortmund and won 16 international caps.