Chelsea have clinched a deal for Brazil Under-20 midfielder Andrey Santos, it was announced on Friday.
Santos had been linked with several of Europe's biggest clubs, including Paris Saint-Germain, Manchester City and Barcelona, after breaking into Vasco da Gama's side last year.
The 18-year-old box-to-box player scored eight goals in 33 games in the Brazilian second tier in 2022, as Vasco won promotion to end a two-season spell outside the top flight.
Chelsea will reportedly pay around £11million for the 18-year-old, whose departure was announced in a club statement from Vasco.
It read: "Vasco da Gama agreed this Friday the permanent transfer of the athlete Andrey Santos to European football.
"The midfielder will defend the colours of Chelsea, from England, in the coming seasons.
"The youngster will end his first spell at the club from Sao Januario at the age of 18 with 38 appearances and eight goals."
Chelsea, mourning the death of their former player and manager Gianluca Vialli on Friday, did not immediately announce the Santos signing.
Santos landed a new contract to run until 2027 with Vasco as recently as September, but he will become the third January arrival at Chelsea.
The Blues confirmed Ivory Coast striker David Datro Fofana as their first recruit under Graham Potter, before signing up Monaco defender Benoit Badiashile for a fee reportedly in the region of €38million (£33.7m).
Chelsea are in need of fresh faces amid an injury crisis and a slump in form, which has seen them win just one of their last eight Premier League games, sliding 10 points adrift of fourth place.