No details have been released regarding the player's transfer fee or contract, but reports indicated that the playmaker would cost around £25 million.

Oscar is representing Brazil at the Olympic Games and played in their pre-tournament warm-up against Great Britain.

The 20-year-old is Chelsea's fourth signing in the off-season, joining Marko Marin and brothers Eden and Thorgan Hazard at Stamford Bridge.

Oscar joined Internacional from Sao Paulo in 2010 and has won the Campeonato Gaucho state championship twice with the Porto Alegre-based side.

He scored 13 goals in 44 matches in all competitions last season and has found the net six times in 20 appearances during the current campaign.