The Daily Mail says Aguero will become the most expensive player in Manchester City's history.
City have agreed a deal of £35million plus add-ons with Atletico Madrid, believed to take the fee up to £38m, for the Argentina striker. In handing him a five-year contract worth close to £200,000 per week, the package to land him could reach more than £85m.
The 23-year-old, who will wear No 16 for City, flew into Manchester on Wednesday morning after cutting short a family holiday in his homeland.
He underwent a three-hour medical before agreeing personal terms at the Etihad Stadium, where he was greeted by hundreds of jubilant supporters and spent time signing autographs.
While the club have yet to announce anything, the player himself said the deal was done on his Twitter account last night.
"I'm already a City player,' he wrote. "Happy to be in this club and this city. Thank you all for the welcome and the reception!"