The 33-year-old ends his 11-year association with the Blues by signing for their London rivals after losing his first-team place to Belgium international Thibaut Courtois at the start of last season.
Cech has signed a three-year deal with the Gunners and will begin next season as Arsene Wenger’s new first-choice goalkeeper ahead of Wojciech Szczesny and David Ospina, who could leave the Emirates Stadium this summer.
In his open letter, Cech admitted he thought he would finish his career at Stamford Bridge, but added: “life doesn’t always turn out the way you think it will”.
The Czech Republic international reserved special praise for Chelsea’s billionaire owner Roman Abramovich, who surprisingly allowed the veteran keeper to complete a move to Arsenal.
Cech hails Abramovich
Cech has offers from other clubs but was keen to stay in London, where his wife and children are settled.
“The limited playing time gave me the chance to refresh and rest mentally as well as make me release just how much I enjoy football at the highest level, because I missed it badly every game I was not involved,” Cech wrote.
“I have the same commitment to football, the same motivation and the same hunger for success as I had at the beginning of my career and I love the challenges brought by the top quality players you face while playing in the Premier League - simply the best and the most challenging league in the world.
“That’s why I spoke to Mr. Abramovich about me staying in the Premier League and I’d like to thank him from the bottom of my heart for his support in this matter. It means so much to me because without him Chelsea Football Club would not be where it is now. He deserves huge credit for what he has done for the club and for all of us.
Cech thanks the Chelsea fans
“I would like to personally thank everyone involved with Chelsea Football Club for their support - all the players, staff, managers and all the coaching staff I have had the pleasure of working with over the years. Without them it would have been impossible for us to have achieved such success.”
And on the fans, Cech added: “But most important of all - a huge thank you goes to all the Chelsea fans. I did everything for you and you gave me your love back. I’ll never forget it. It will stay with me forever. We will meet again but this time I will be in the other goal - I hope you will remember our history and understand it is time for me to begin a new adventure.”
Arsenal players excited by Cech arrival
Interestingly, Cech did not thank Jose Mourinho for his part in the transfer, suggesting the Portuguese coach was extremely reluctant to see his back-up goalkeeper join Wenger’s squad.
That there’s no love lost between Mourinho and Wenger is no secret - and it wouldn’t be a huge surprise if the former viewed Cech’s decision as something of a betrayal.
Speaking to Arsenal's official website, Cech said: “I’m really excited about joining Arsenal Football Club and can't wait to join up for pre-season. I have the same commitment to football, the same motivation and the same hunger for success as I had at the beginning of my career, and I love the challenges brought by the top quality players you face while playing in the Premier League.
"When Arsène Wenger spoke to me about his ambitions for this club, and how he saw me as part of this team, the decision was clear.”
Several Arsenal players took to Twitter to express their excitement after hearing the news, including both Theo Walcott and Aaron Ramsey.
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