Barcelona have completed the 31million euros (£27.5million) signing of midfielder Arthur from Brazilian club Gremio.
The Catalan giants announced the news on their official website, confirming the player will sign a six-year contract with a buy-out clause of Euros 400m (£350m).
In a statement the club said: “FC Barcelona and Gremio de Porto Alegre have agreed the transfer of the player Arthur Henrique Ramos de Oliveira Melo, following the agreement the two clubs reached in March.
“The agreement will see the Brazilian player immediately join the squad.”
The 21-year-old, who will join compatriot Philippe Coutinho in the Barcelona squad, is yet to make a full senior appearance for the national team.
However, he has come through the Brazilian junior teams and starred in a Gremio team which won both the Copa do Brasil and the Copa Libertadores.
Arthur started his career at his local club Goias before being spotted in 2010 by Gremio, then under the charge of former Chelsea boss Luiz Felipe Scolari.