Fernandinho has completed his £34 million transfer to Manchester City from Shakhtar Donetsk.
The 28-year-old Brazilian is officially the club's second signing of the summer, with winger Jesús Navas' arrival from Sevilla imminent.
Fernandinho had aired his desire to join City on Twitter over the last month.
“This is a change, a challenge and a chance that I have been waiting a long time for," Fernandinho told City's website. "Playing in the Premier League for City is like a dream.
“My ambition here is to win all the titles, the team here is strong, and so is the greatness of the club and the supporters. Professionally this is a spectacular thing. Playing for a huge club in a huge league makes me so happy. I hope I will be able to repay City for what they have done for me.
“I know I will face challenges but I am prepared for them. Every player at a high level faces pressure and must respond and I am ready for that too. I know a lot about City. Ever since they expressed an interest in me, I have been learning more."
A defensive midfielder, Fernandinho will complement City's indomitable Yaya Touré for a formidable central midfield pairing.
City's eagerness to recruit new players early suggests their determination to atone for their shambolic summer in the transfer window last year.
The club eventually finished 13 points behind Barclays Premier League champions United and lost the FA Cup final to Wigan Athletic.
After Robin van Persie rejected them in favour of neighbours United, the Blues made a string of rash deadline day signings, with all but young defender Matija Nastasić underperforming.
Fernandinho, who has won five caps with the Seleção, spent eight years with Shakhtar, becoming an integral part of their rising stock in the Champions League.
City will officially confirm Manuel Pellegrini as Roberto Mancini's successor early next week.