The Corinthians forward has arrived in London ahead of a medical, and while the Blues are yet to confirm any deal, the 26-year-old revealed the move will be finalised soon.
Pato told Sky Sports: "I’m so happy. I stay here for my dream. Chelsea is my new home. Thanks to Chelsea for support. Thanks to my fans for support on Instagram, Twitter and Facebook.
"I need to play. I don’t know what to say because I’m so happy. I’m very anxious [to play] and I want to know my new friends and players in the team. I really want to play in Chelsea."
READ MORE | Ramires leaves Chelsea
He will become the first signing of Chelsea caretaker boss Guus Hiddink's second spell in charge as the club look to improve on their current position of 13th in the Premier League table.
Pato, who has been capped 28 times by Brazil and scored 10 goals, can operate on either flank and also as a striker, meaning he will provide competition for Diego Costa and Loic Remy up front.
On a busy day of transfer activity at Stamford Bridge, Ramires left the club for Chinese club Jiangsu Suning in a £25 million deal.