Willock has been with the Gunners since 2003 but the highly-rated 19-year-old forward is yet to make a first-team appearance for Arsene Wenger in the Premier League.
The England Under-19 international is out of contract at the end of June which has seen him be linked with a move away from the Emirates ahead of the 2017/18 campaign.
Record claim Willock is now closing in on a switch to Primeira Liga outfit Benfica where the teenager will be hoping for more regular game-time.
It’s understood the youngster has been in Portugal discussing a potential move to Benfica and talks have reached an advanced stage this week.
Willock’s only two first-team appearances for Arsenal came in the EFL Cup last season.
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His brother, Joe, is also reaching the end of his current deal in north London.