Hours after pictures of Bony holding aloft a City shirt emerged on Twitter, the English Premier League champions have finally confirmed the signing of the Ivorian striker.
Bony, who scored more EPL goals than any other player in 2014, is currently with the Ivory Coast national team preparing for the upcoming Africa Cup of Nations, which begins in Equatorial Guinea on Saturday.
And it was the Ivory Coast Football Federation which prematurely broke news of the transfer by posting the picture on Twitter, sparking a spiky response from Bony's now former employers Swansea.
The Welsh club insisted the deal had not been completed, but now its EPL rivals City have announced the capture of the 26-year-old on a four-and-a-half-year deal.
"It's a great feeling for me, it's a big honor to be here and it's a great challenge," Bony told City's official website.
"As a player it's always good to be part of one of the biggest clubs in the world and it's a good opportunity for me to be in that situation now -- I'm really proud.
"I felt excited to wait for this moment and now it's come, it's fantastic."
Bony joined Swansea from Dutch team Vitesse in 2013 and has forged a reputation as prolific goalscorer.
He scored 15 EPL goals in his debut season and has found the net nine times in the current campaign, including one against his new team in November.
The move sees Bony join forces with his international teammate Yaya Toure, who has been with City since 2010.
"I speak with Yaya every day on international duty and I think he will help me to become a better player and a more clinical striker," added Bony. "I'll be playing with great players here at City and this is an opportunity for me to work hard and to take my chance."
City will be hoping Bony can produce the goals that will help Manuel Pellegrini's team maintain the Premier League crown and succeed in the European Champions League.
Bony will be expected to fill the hole left in the team by Sergio Aguero, the Argentine who has scored 14 league goals for City this season but who is currently sidelined through injury.