The Gunners made the announcement late on Friday night, with the France international signing for an undisclosed fee.

Diarra told "I have great respect for the manager Arsene Wenger and am attracted by the style of football that the team plays. Of course I am excited by what the future holds and keen to play my part in helping Arsenal fight for trophies this season and for years to come."

Gunners boss Arsene Wenger said: "Lassana is a multi-functional player, making him a great addition to our squad. Not only is he hard working, he has a creative edge and is comfortable playing in the middle of the pitch or at right back."