Chelsea have completed the signing of Brighton midfielder Moises Caicedo for a £100m fee which could rise to a British club record of £115m.
But Caicedo's preference was Chelsea and they finally succeeded with a bid on Sunday evening after having a succession of offers rejected.
"I didn't have to think twice when Chelsea called me, I just knew I wanted to sign for the club," Caicedo said.
"It's a dream come true to be here and I can't wait to get started with the team."
The additional £15m in payments is based mostly based on appearances and Brighton expect to receive the entire £115m in a short period of time.
The Seagulls have also negotiated a significant sell-on clause for the midfielder.
If Chelsea pay the full £115m fee it would mean they break the British club record twice in 2023, following the £107m purchase of Argentina midfielder Enzo Fernandez in January.
"Moises has proved himself as a standout player in European football over the past 18 months," said Chelsea co-sporting directors Laurence Stewart and Paul Winstanley in a statement.
Brighton director of football David Weir believes Chelsea are signing "one of the top midfielders in the world".
Match of the Day 2: Caicedo is 'perfect match' for Chelsea - GivenBrighton had set a fee in excess of £100m for Caicedo this summer and said they felt no-one would reach it.
"Moises expressed a strong desire to move on, and at that point it was crucial our valuation was met in full," said Brighton chairman Tony Bloom.
In his news conference before the Seagulls' season opener against Luton, manager Roberto de Zerbi said he had "already forgotten" about Caicedo, adding: "Bigger clubs can buy our players but they can't buy our soul or spirit."
Caicedo joined Brighton from Ecuadorian side Independiente del Valle for £4m in February 2021, although he did not make his Premier League debut until April 2022.
He asked to leave Brighton in the January transfer window earlier this year and Arsenal had multiple offers turned down for the midfielder before he signed a new contract until 2027 in March.
Caicedo will be Chelsea's eighth signing of the summer, following Axel Disasi, Christopher Nkunku, Nicolas Jackson, Lesley Ugochukwu, Angelo Gabriel, Robert Sanchez and Diego Moreira.
New manager Mauricio Pochettino has been tasked with overhauling the squad and vastly improving on last season's 12th-place finish in the Premier League.
Mateo Kovacic, Edouard Mendy, Kalidou Koulibaly, N'Golo Kante, Mason Mount, Kai Havertz, Christian Pulisic, Ruben Loftus-Cheek, Ethan Ampadu, Pierre Emerick-Aubameyang, Abdul Rahman Baba and former captain Cesar Azpilicueta have all departed so far this summer.
Chelsea opened their Premier League season with a 1-1 home draw against Liverpool on Sunday.