London, Aug 25 - Troubled British singer Amy Winehouse is suing her ex-mother-in-law Georgette for selling one of her love letters.

According to thesun.co.uk, the note, which was sold, was written by Winehouse for her ex-husband Blake Fielder-Civil when he was in jail for assault and preventing justice. Now the singer is suing for copyright infringement and wants about $81,000 compensation.

'Amy was furious the private letter was used to make money,' said a friend of Winehouse.

Winehouse was never on good terms with Georgette who in the past had accused her of turning her son to drugs.

Winehouse and Fielder-Civil were married in 2007 but divorced recently. They spent most of their marriage apart since Fielder-Civil was in jail.

Right now the singer is trying to reconcile with her ex-husband.