The Portugal international, a member of their Euro 2016-winning squad, signs a one-year deal at Stamford Bridge and will cover Thibaut Courtois and Asmir Begovic.
Chelsea has completed the signing of goalkeeper Eduardo from Dinamo Zagreb.
Eduardo, who was a member of Portugal's squad as they won Euro 2016 in France, has signed a one-year contract at Stamford Bridge, and is set to provide cover for Thibaut Courtois and Asmir Begovic.
The goalkeeper has won 35 caps for his country, and made a total of 98 appearances for Dinamo.
"Having the opportunity to come to the Premier League and to Chelsea, to such a big club, it is an easy decision to make," he told Chelsea's official website.