Chelsea have agreed a £30m deal to sign attacking midfielder Willian from Russian club Anzhi Makhachkala, subject to a work permit hearing.
The 25-year-old Brazilian was close to joining Tottenham after having a medical on Wednesday.
But it is understood Chelsea made their move at around 18:00 BST on Thursday, with a fee and personal terms agreed within 24 hours.
Willian will have a medical before his work permit hearing next week.


The transfer was made possible after Chelsea owner Roman Abramovich, whose fellow Russian oligarch Suleyman Kerimov owns Anzhi, intervened.
Willian expected to join Tottenham, but when the Blues stepped in, he felt the chance to play Champions League football was too good to reject.
Sources close to the player said Chelsea have made enquiries or offers for his services in every transfer window since 2011.
Willian will become the Stamford Bridge club's third major summer acquisition following the arrivals of Germany forward Andre Schurrle and Netherlands midfielder Marco van Ginkel.
Earlier on Friday, Blues manager Jose Mourinho indicated that Willian would choose Chelsea over Tottenham.
When asked whether the Brazilian had chosen to join his club, Mourinho nodded.
The Portuguese added: "I know what the player wants, so in this moment we cannot hide."

Willian joined Anzhi in January for a reported £30m after five-and-a-half seasons with Shakhtar Donetsk in Ukraine. But he became available as the Russian club attempt to cut costs after a change in strategy by their owner.
Tottenham had expected to break their transfer record and make Willian their fifth major summer signing.
"I couldn't say much in previous news conferences," Mourinho said.
"I have to answer your questions and try to be honest, but at the same time try to hide a few things.
"I'm happy with my squad, but every one of us managers, we say we are happy, but we are always unhappy.
"We always want something of more quality and we never close the door to the possibility of adding more quality."
Willian's arrival would further strengthen a squad full of attack-minded midfielders, such as Eden Hazard, Oscar, Kevin De Bruyne and Schurrle.
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