The 18-year-old Chile Under-20 international has made a move to Stamford Bridge.
The 18-year-old, who can operate either as a left back or left winger, has signed a contract which will keep him at Stamford Bridge until the summer of 2018.
Cuevas came through the youth ranks at O'Higgins to make a handful of senior appearances, before shining with Chile at this summer's Under-20 World Cup, playing in four of the team's five matches.
The Blues moved to tie up the deal after the youngster impressed on trial at the club in November and he was expected to sign this summer.
Cuevas becomes Chelsea's fourth signing of the transfer window, following the arrivals of Andre Schurrle from Bayer Leverkusen, Marco van Ginkel from Vitesse and free agent Mark Schwarzer.