Manchester City say Spain midfielder Rodri is a "perfect fit" for the team after moving from Atletico Madrid for a club record £62.8m.
Rodri, 23, joins on a five-year deal and is City boss Pep Guardiola's second signing of the summer after defender Angelino rejoined from PSV Eindhoven.
"Rodri has proven himself as a hugely talented, young midfielder," said director of football Txiki Begiristain.
"He has as all the attributes we are looking for."
He added: "He works hard defensively, makes himself available to receive the ball and uses it well when in possession. We are confident he will be a success."
Rodri will wear the number 16 for City, the same number worn by Sergio Aguero when he first moved to the Etihad from Atletico.
The fee for the Atletico academy graduate surpasses City's previous record of £60m in signing Riyad Mahrez in 2018.
"What City have achieved in the last two years has been amazing and I'm looking forward to being part of such a talented squad," said Rodri.
"It's not just the titles they have won, but the way they have managed it, playing attacking football at all times.
"It's a style that excites me, as do the club's ambitions."
Rodri rejoined Atletico in May 2018 after three years at Villarreal and made 34 league appearances as they finished second in Spain's top flight.
He made his international debut in a friendly against Germany last year and has made six senior international appearances.
City had made Rodri one of their main targets this summer, with Guardiola keen to sign a defensively minded player to bolster the Premier League champions' squad.
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