Stylish midfielder Jack spent last season on loan to Bournemouth, making 27 appearances in the Premier League.
It was the academy product's second loan spell away from Arsenal, having joined the club at the age of nine. Previously he spent the second half of 2009/10 at Bolton Wanderers, shortly after he broke through into the Gunners first team.
He made his Arsenal first-team debut aged just 16 and 256 days, in a Premier League win over Blackburn Rovers, making him our youngest-ever league player. He also broke our record for the youngest player in European competition, aged 16 and 329 days, when he played against Dynamo Kiev in November 2008.
Later that season he played a major part in Arsenal's FA Youth Cup success, scoring in the final against Liverpool.
Capable of playing in either an attacking or defensive midfield role, Jack is a fearsome competitor, never shirking a challenge and possessing plenty of stamina. His impressive passing ability is also one of his key weapons, and he's scored some memorable goals in his Gunners career. He won the Match of the Day's Goal of the Season in both 2013/14 and 2014/15.
A senior England international from the age of 18, he particularly excelled during the Euro 2016 qualifying campaign, scoring his first international goals in a win over Slovenia in June 2015. He previously won the Victory Shield twice, as part of the England youth setup.
He was named PFA Young Player of the Year in 2010/11, and also earned a place in the PFA Premier League Team of the Year that season.