Sanchez made 23 league appearances for Brighton last season before losing his starting place to Jason Steele.

"Robert is a good guy and a really good player, but being a coach sometimes means making difficult and painful decisions for the team," Brighton boss Roberto de Zerbi said.

"I wish him good luck for the future."

Sanchez joined Brighton as a 15-year-old in 2013 from La Liga side Levante and signed his first professional contract with the Seagulls two years later.

After loan spells with Forest Green Rovers and Rochdale he made his Premier League debut for Brighton in a 2-1 defeat at Tottenham Hotspur in November 2020.

He will compete with fellow Spaniard Kepa Arrizabalaga at Chelsea after Senegal goalkeeper Edouard Mendy moved to Saudi Pro League side Al-Ahli in June.

"Robert has repeatedly proved himself in the Premier League and been capped by his country," Chelsea's sporting directors Paul Winstanley and Laurence Stewart said in a statement.

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

The goalkeeper is Chelsea's sixth summer signing as they prepare for Pochettino's first season in charge.

The Blues have bolstered their attack by adding Christopher Nkunku from RB Leipzig for £52m and Nicolas Jackson from Villarreal for a reported £32m.

They also signed France defender Axel Disasi for £38.5m from Monaco on Friday.

French midfielder Lesley Ugochukwu may go on loan after joining for £23m from Rennes on Tuesday, while 18-year-old Brazilian winger Angelo Gabriel arrived from Santos for an undisclosed fee.

There have also been a number of high-profile departures from Stamford Bridge.

Germany forward Kai Havertz joined Arsenal in a £65m deal, England midfielder Mason Mount was sold to Manchester United for £55m plus £5m in add-ons, while Manchester City signed Croatia midfielder Mateo Kovacic for an initial £25m.

Mendy and Kalidou Koulibaly both joined Saudi clubs, as did N'Golo Kante when he signed for champions Al-Ittihad, while England midfielder Ruben Loftus-Cheek and United States forward Christian Pulisic have both completed moves to AC Milan.