London - Arsenal chief executive Ivan Gazidis is to leave the club to take up a similar post at Italian giants AC Milan, the Premier League club announced on Tuesday.
Speculation that Gazidis - who oversaw Unai Emery's appointment to replace Arsene Wenger in May - will depart for Italy has been rife for some time.
Now the move has been confirmed, with Raul Sanllehi, currently head of football relations at the Emirates Stadium, to become head of football when Gazidis heads to Milan.
Arsenal's chief commercial officer Vinai Venkatesham will take over the role of managing director at the same point.
Gazidis, 54, has reportedly been offered £3.6 million - a £1 million increase in his present salary - and an equity stake in the AC Milan by the American owners Elliott Management, who took over in July.
Gazidis, who will leave Arsenal by the end of October, has worked for the Gunners since 2009 and has been behind a radical change in management structure at the Emirates.
He played a major part in introducing roles such as Sanllehi's, as well as that of head of recruitment - a post held by Sven Mislintat.
Those appointments wrestled some power away from Wenger, whose 22-year tenure came to a close at the end of last season.
Gazidis wrote a lengthy message to Arsenal supporters, in which he described his impending move as the "hardest decision of my life".
There have been significant changes behind the scenes at Arsenal in recent months, with majority shareholder Stan Kroenke last month launching a bid to take overall control of the club through his company Kroenke Sports and Entertainment (KSE).
His son, Josh Kroenke, is deputy chairperson of KSE and praised the work of Gazidis during his tenure at Arsenal.
"It has been a pleasure working with Ivan. We will miss the wisdom, insight and energy he brought to our club on a daily basis over the past decade," he said in a statement announcing Gazidis' departure.
Milan confirmed that Gazidis will begin working with the club from December 1, describing him as a "world-class football executive".
Arsenal, who have not won the Premier League title since 2004, are currently in seventh place, six points behind leaders Chelsea.