Sanchez, who lost his place to Jason Steele during the second half of last season, will offer competition for Kepa Arrizabalaga following the departure of Edouard Mendy to Saudi Arabian club Al-Ahli.

"We're very pleased to welcome Robert to Chelsea and he adds further quality to our goalkeeping unit," Chelsea sporting directors Paul Winstanley and Laurence Stewart said.

"Robert has repeatedly proved himself in the Premier League and been capped by his country.

"We are excited to watch him work with Mauricio (Pochettino) and his coaching team during the season ahead."

Sanchez becomes Chelsea's sixth summer signing as they prepare for Pochettino's first season in charge.

The deal is reported to be worth £25 million ($32 million) with an additional sell-on clause included.

Spain international Sanchez, 25, worked with Chelsea goalkeeping coach Ben Roberts when he was at Brighton. Roberts left for Stamford Bridge in September 2022.

New Blues manager Pochettino is overhauling his squad following the club's worst Premier League season in almost 30 years.

Chelsea have also been linked with a move for Seagulls midfielder Moises Caicedo, with Brighton said to be looking for a £100 million fee.

They open their new Premier League campaign at home to Liverpool on August 13.