Arsenal chief executive Ivan Gazidis will leave the Gunners at the end of October to join AC Milan.
Gazidis has been at Arsenal for the last 10 years and was responsible for replacing the club's long-serving manager Arsene Wenger with Unai Emery ahead of the 2018-19 campaign.
However, the 53-year-old is stepping away from his role at the Emirates Stadium to take up a new role in Italy on December 1.
Gazidis will be replaced by head of football relations Raul Sanllehi and chief commercial officer Vinai Venkatesham.
"For the last 10 years I have been privileged to dedicate myself to this great club. Arsenal is entering a new chapter and I have done everything I can to ensure that it is strongly placed to take on that challenge. This includes world-class facilities and outstanding leaders in every sector who carry the values of the club, including, of course, Unai Emery, Raul Sanllehi and Vinai Venkatesham in whom I have enormous faith," read a statement from Gazidis on Arsenal's official website.
"We have rebuilt the off-field capability of the club, which is necessary for prolonged success in modern football, we have recently concluded new primary partnership deals that, together with the new league broadcast deals, secure our medium term financial future, we have updated our stadium and rebuilt our training facilities so that they are now world class and we have transitioned to a new football structure that is capable of taking the club confidently into the future.
"I am proud to say we have done this while building on the club's progressive social values, leading the way on the women's game as well as diversity and inclusion and establishing The Arsenal Foundation, which supports these values around the world in difficult places such as Iraq and Jordan and complements our extraordinary work in our local community. This will remain central to the club's philosophy.
"Given this platform, I know many will think this is a strange time to be leaving but I believe it is the right time for me and for the club. Change and succession is not only inevitable for a club like Arsenal, it is necessary if it is continually to keep moving forward. One of my primary responsibilities as chief executive has been to make sure that there is good succession planning in every position in the club, including my own."
Gazidis has reportedly been handed an increase on his yearly salary at Arsenal, in addition to an equity stake in Milan.
