If my roomate forged my signature on the lease, is it still valid?

okay so me and my roomate have a one year lease up aug 1st, i wanna move out though (hes become a dbag). when we signed the lease i was at work and he forged my signature on the documents. if you compare the signature to any of my real signatures it is quite apperent i did not sign the document. my question is if i moved out would i still be legally responsable for the lease?