Diarra signed from Chelsea...
Here's the statement from the club:
Arsenal Football Club is pleased to confirm that Lassana Diarra has signed for the Club from Premier League side Chelsea, on a long term contract for an undisclosed fee.
Diarra (22) who is comfortable playing in midfield or defence, has spent the last two seasons with Chelsea, where he collected a Carling Cup winner's medal in February this year after playing in the final against the Gunners.
Awarded individual accolades of Young Player of the Year by both former clubs, Le Havre (2004) and Chelsea (2006), Diarra has gone on to play for France in their Euro 2008 qualifying campaign.
Lassana Diarra said: "I have great respect for the manager Arsène 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."
Arsène 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."
Lassana Diarra will wear the number 8 shirt.