Spain international Rodri has become Manchester City's second summer signing after completing his move from Atletico Madrid.
The 23-year-old midfielder has signed a five-year deal, the Premier League club announced.
Rodri officially became a City player on Thursday, the day after the LaLiga outfit revealed the €70million - around £62.8million - release clause in his contract, which had four years to run, had been triggered.
A statement on the reigning champions' official website said: "Manchester City are delighted to announce the signing of Spanish midfielder Rodri.
"The 23-year-old joins on a five-year deal from Atletico Madrid and follows Angelino to become Pep Guardiola's second signing of the summer."
City have not confirmed the fee, but the value of the release clause is more the £60million City paid Leicester for Algeria international Riyad Mahrez last summer.
Rodri said: "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.
"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.
"I can't wait to start working with Pep Guardiola and my new team-mates, and hopefully we can achieve great things together."
The 6'3" holding midfielder began his career as a youth player at Atletico before moving to Villarreal in December 2015. He returned to Madrid in June last year for a reported fee of £20million.
He made 47 appearances for the club last season as they finished runners-up to champions Barcelona and eight points clear of city rivals Real Madrid.
City's director of football Txiki Begiristain said: "Rodri has proven himself to be a hugely talented, young midfielder who has all the attributes we are looking for.
"He works hard defensively, makes himself available to receive the ball and uses it well when in possession.
"He is a perfect fit for Pep Guardiola's team and we are confident he will be a success."