The Brazilian striker, who is currently on the books of Corinthians, has been heavily linked switch to Stamford Bridge over recent days.
However, it appeared that the move may fall through following speculation that interim manager Guus Hiddink was unsure whether Pato would be an upgrade on his current attacking options.
But, according to Sky Sports News, the deal has now been finalised, with the 26-year-old initially arriving in West London on a six-month loan basis.
The report adds that a clause in the deal will allow Chelsea to sign the frontman permanently in the summer.
By Taiwo Oyedeji
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