"Just arrived in Manchester to tie up the details of the signing for City," Aguero said on his Twitter feed, which can be reached via a link on his official website.
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"Everything is going well," he added. "I'll tell you more in a little while."
Juventus had also been chasing the diminutive forward who upstaged team-mate Lionel Messi at the Copa America by scoring three times in four games.
Aguero, 23, was one of the few bright spots for Argentina, who bowed out of the event they were hosting at the quarter-final stage after a penalty shootout defeat to eventual champions Uruguay.
Aguero, married to one of Diego Maradona's daughters, has spent five seasons at Atletico Madrid where he won the Europa League in 2009/10. He is expected to replace unsettled compatriot Carlos Tevez at the Premier League side.
He was raised at Independiente where he made his professional debut as a 15-year-old.
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