Chelsea have signed Spain defender Marc Cucurella from Brighton on a six-year contract.
The 24-year-old left-back scored one goal in 38 games in his only season for the Seagulls after joining from Spanish club Getafe.
"I'm really happy. It's a big opportunity for me to join one of the best clubs in the world," said Cucurella.
"I'm going to work hard to be happy here and help the team."
Brighton said they have received a record transfer fee for Cucurella, surpassing Ben White's £50m move to Arsenal last summer.
A Barcelona academy graduate, Cucurella has won one senior cap for Spain and played for the under-23 side that won silver at the 2020 Tokyo Olympics.
Last month Brighton rejected a £30m bid from champions Manchester City for Cucurella, who handed in a transfer request after City expressed an interest.
"We did not want to lose Marc, but he wanted the opportunity of playing Champions League football with a view to accelerating his progress to Spain's World Cup squad," said Brighton manager Graham Potter.
"Of course we are disappointed to see Marc leave, but we wish him well for the future.
"He had an excellent first season in the Premier League, deservedly winning both our player of the season awards, and has been an absolute pleasure to work with over the past 12 months."
Cucurella is the second big-money departure from Brighton this summer after midfielder Yves Bissouma joined Tottenham for £25m plus add-ons.
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