Arsenal have signed Germany forward Kai Havertz from Chelsea on a five-year deal until 2028 for £65m.
The 24-year-old spent three years at Stamford Bridge after joining from Bayer Leverkusen for £71m.
The fee for Havertz, who scored nine goals for the Blues last season, could rise with add-ons.
Havertz has scored 19 goals in 91 Premier League appearances and hit the winner in the 2021 Champions League final against Manchester City.
He moves across London as Mikel Arteta looks to strengthen his Arsenal side following qualification for the Champions League after a six-year absence.
In a statement on his social media channels, Havertz said it was “with a heavy heart” that he was saying goodbye to Chelsea’s fans.
“A big thank you for all your support, we achieved a dream of winning the Champions League together,” he added.
Speaking on the Arsenal website after his transfer had been announced, Havertz said his aim was to “win trophies” with his new club.
“It’s super exciting for me to be joining this amazing club and to be part of the Arsenal family,” said Havertz. “This club has such a big history, and I hope we can achieve lots of things.
“The mentality in the Arsenal squad is very high and you can feel that. That was one of the reasons why it has been so hard to play against Arsenal recently.
“The aim is to win trophies and I’m going to give everything to do that for the supporters and everyone at the club. I’m now looking forward to meeting all the players and the staff when we come back for pre-season.”
Arsenal have also submitted a third bid worth £105m for West Ham and England midfielder Declan Rice.
Chelsea are seeking to reduce their squad size and sold Croatia midfielder Mateo Kovacic to Manchester City on Tuesday, while fellow midfielder Ruben Loftus-Cheek is close to joining AC Milan.
N’Golo Kante has agreed a deal with a Saudi Arabian team, while goalkeeper Edouard Mendy and defender Kalidou Koulibaly have moved to the Saudi Pro League with Al-Ahli.
Midfielder Tiemoue Bakayoko has also left the club as a free agent.
The new ownership at Chelsea want to avoid letting players enter the final two years of their deals and Havertz, whose contract had been due to run out in 2025, did not agree an extension at the club.