1253 GMT January 19, 2019
The 25-year-old Brazil midfielder, snared for a reported £60 million (€70.5 million), becomes just the latest top player in his prime lured to the mega-rich Chinese Super League, AFP reported.
He is due to finalize the deal in Shanghai in the "coming days", said the Chinese club, which is coached by ex-Tottenham Hotspur manager Andre Villas-Boas.
"I'm very happy to sign to SIPG. This is an important day for me to join to my new family in China," Oscar said in a video statement released by SIPG.
As well as Asia's record signing, Oscar will also become Chelsea's biggest sale, beating compatriot David Luiz's £50-million move to Paris Saint-Germain in 2014.
Chinese Super League clubs have already splashed out more than $400 million on players this year, after President Xi Jinping laid out a vision of turning the country into a football power.
Chinese teams broke the Asian record three times in just 10 days in the January-February transfer window, and moved it still higher when Brazil's Hulk joined SIPG for €55.8 million in July.
Significantly, Chinese clubs are now competing with European rivals for world-class players, who are opting for China's astronomical pay packets over the chance of a career in football's top leagues.
Oscar's ex-Chelsea teammate Ramires 29, and Alex Teixeira, 26, are other highly rated Brazilians in their twenties to join the Super League for record sums this year.
Other world-renowned players in China include Hulk and Jackson Martinez, both 30, and Ezequiel Lavezzi and Graziano Pelle, both 31.
According to reports, some of the players are now among the highest paid footballers in the world.
A Chelsea statement said Oscar will join SIPG at the start of the January transfer window, noting he has won the Premier League, League Cup and Europa League titles during his four-and-a-half years at the London club.
"Shanghai SIPG has formally completed the transfer agreement of Brazil football player Oscar with Chelsea," the Chinese club said on its official social media account.
"Oscar will arrive in Shanghai in the coming days to officially join SIPG."
He has been a target of Shanghai's new manager Villas-Boas since the Portuguese managed Tottenham Hotspur in the 2012/13 season, but opted to join Chelsea instead.
Last week Chelsea boss Antonio Conte, when asked to comment on Oscar's impending transfer, called China's financial muscle "a danger for all teams in the world".
Chinese state media has also warned of a "bubble" developing in China's football industry, saying total spending this year had topped $1 billion.
Communist Party mouthpiece the People's Daily said 8 billion yuan ($1.15 billion) had been spent in 2016, a sum which "far exceeded the economic value brought to the league".
The breakneck spending shows no sign of slowing, however, with Argentine forward Carlos Tevez also expected to move to China when the transfer window opens in January.
Peril to PL
Arsenal boss Arsene Wenger admitted he was surprised by Oscar's £60 million move from Chelsea to Shanghai SIPG, adding the money being ploughed into Chinese football is potentially a threat to the Premier League, which has been the most powerful financial force in the market for many years.
'Yes, it's a surprise, it's a distortion," said Wenger. "Basically when you're a football player you want to combine the quality of the competition with the quantity of your wages.
"It's a surprise to me, but when I was in Japan, we had many Brazilian players. At the moment I think Oscar moves because he doesn't play in the Premier League. China gives him that opportunity as well,..they invest a lot of money at the moment.
"Will it be a future problem for the Premier League? It could become [one]."