New Liverpool winger Alex Oxlade-Chamberlain says his "ongoing development" is the reason why he decided to leave Arsenal.
The Englishman was initially all set to move to Stamford Bridge but he rejected a move to Chelsea to join the Reds.
He leaves the Gunners after manager Arsene Wenger made it clear this month that he was going to "100% stay at the club".
"After six years, three FA Cup wins and countless incredible memories, the time has come for me to move on from Arsenal," Oxlade-Chamberlain wrote on Instagram.
"I want to publicly thank Arsene [Wenger], the coaching and club staff and my amazing team mates for all of the incredible opportunities I have been given.
"Thank you so much to you, the fans, who have always had my back – I honestly couldn't be more grateful.
"The club, and my time here, will always mean a massive amount to me.
"I know my choice might come as a surprise to many, and the decision to leave was tough after being a part of the club for so many years, but I feel that this move is right for the next stage in my ongoing development."