Arsenal have blamed a hacker after a pornographic image was tweeted from the club's official account. The image, which was deleted immediately shows a woman engaging in oral sex and was accompanied by the text: "Here's a snapshot of Arsenal training in Germany. We'll have a gallery for you later today."
It was later deleted but not before users had their say.
Arsenal said in a statement: "We had a hack on our account which was quickly spotted and necessary steps taken."
The tweet appeared to originate from 2012.
One user's theory was that the tweet accompanied a link to an external site, the preview image for which was altered to the pornographic one.
The Gunners take on Crystal Palace when they return to Premier League action on Monday evening.