Chelsea have completed the signing of Ukraine forward Mykhailo Mudryk from Shakhtar Donetsk in a deal worth up to £89m.
The 22-year-old has agreed an eight-and-a-half-year deal for 70m euros (£62m), plus a further 30m euros (£27m) in bonuses.
"I'm so happy to sign for Chelsea," said Mudryk.
Arsenal also wanted Mudryk, who scored seven goals in 12 league appearances for Shakhtar this season.
"This is a huge club, in a fantastic league and it is a very attractive project for me at this stage of my career," he said.
"I'm excited to meet my new team-mates and I'm looking forward to working and learning under Graham Potter and his staff.