Chelsea have revealed that Willian has agreed to join the club, subject to a work permit being granted.
It appeared that the Brazilian was heading for Chelsea's London rivals Tottenham Hotspur after he completed a medical with the White Hart Lane-based outfit last week.
However, reports over the last few days suggested that the Blues had entered the race to sign the 25-year-old, who had been made available for transfer by Russian club Anzhi Makhachkala.
Now, in a short statement on the club's official website, Chelsea have confirmed that they have reached a settlement with both the player and his club.
"Chelsea Football Club can confirm an agreement has been reached with both Willian and his club Anzhi Makhachkala for the transfer of the Brazilian player," read the statement.
Willian's work permit application will be heard on Wednesday.
