Chelsea have signed the 26-year-old former AC Milan forward on loan from Brazilian club Corinthians.
Pato said: “I am so happy to sign for Chelsea. It is a dream for me. I am looking forward to meeting and getting to know my new team-mates and cannot wait to play.
“I thank Chelsea for their support and hope I can repay this faith.”
Confirmation of Pato’s move to Stamford Bridge came just hours after Chelsea interim boss Guus Hiddink denied the Brazil forward’s signing is a gamble.
“It’s not a gamble,” said Hiddink, ahead of tomorrow’s FA Cup fourth-round tie at MK Dons. “I said we are short of strikers, of available strikers, so I said let’s go for it.
“The green light was mine. Coming on loan makes it possible to have a good view on him, whether he is able to adapt to the high demands of the club and the league.”
Pato showed immense promise early in his career, but has been hampered by injuries in recent seasons.
It is uncertain when he will first be available to select.
Hiddink described the move as “a brave step” and the success or failure depends on the player. “I will help him to make that next step, but it’s up to him,” he said.
New York Red Bulls defender Matt Miazga’s move is near completion, too.
“He’s an up-and-coming youngster. I’ve not watched much of him,” said Hiddink.
He was asked about the contribution of Diego Costa, who has six goals in six games after a prior fallow spell under Jose Mourinho. He netted last Sunday’s decisive strike in the Premier League win at Arsenal.
“Diego is delivering beyond expectations,” said Hiddink.
“He’s of huge importance for us. We’re depending a lot on him, too much sometimes.”
Yet Chelsea could be increasingly reliant on the Brazil-born Spain striker as Loic Remy could be allowed to leave before Monday’s transfer deadline, while Falcao (thigh) remains injured.
Hiddink played down speculation that England vice-captain Gary Cahill is unsettled, saying he expects the defender, who earlier this season signed a new four-year contract, to stay at the club.
“There was no hint from his side ‘Can I leave the club?’ Nothing,” said Hiddink. “I think the club will have him in the upcoming years.”
The Blues did not progress beyond the fourth round last season as League One Bradford came from two goals down to win 4-2 at Stamford Bridge in arguably the biggest cup upset in recent history.
Dons midfielder Darren Potter says his side must follow the lead of old boy Dele Alli and show they belong in Chelsea’s company. “Dele’s a prodigious talent. He’s shown his fearlessness already. I don’t think the ability and the composure of the lad comes as any surprise to anybody that knows him here, just how rapidly he’s risen to play for England and score his first goal.
“W respect Chelsea but we’re also on a level playing field when we go out there, so we’ll be doing everything we can to try to get a result.”