Amy Winehouse has been arrested....and it's not for drugs. The retro-soul singer is being held on suspicion of assault at the Holborn Police Station.

Wino allegedly headbutted a guy while she was out at a bar earlier this week. We're not sure if the bee-hive softened the blow or not.

The max sentence in London for assault is six months in jail. If she goes, she will join her hubby, Blake Fielder-Civil who is already in the clinker.