Besiktas have signed Egypt international midfielder Mohamed Elneny on a season-long loan from Arsenal.
The 27-year-old has made 89 appearances for the Gunners in all competitions since joining from Swiss side FC Basel in the summer of 2016.
However, he fell out of favour following the appointment of Unai Emery as manager last summer.
The midfielder made 17 appearances in all competitions during the 2018-19 season, with just eight of those coming in the Premier League.
He has not featured at all this campaign, with Emery publicly stating earlier this month that he was free to leave.