Illinois Additional Defendant Signatures, Names, & addresses are documents that must be filled out and signed by defendants in civil litigation cases in the state of Illinois. These documents contain the name of the defendant, their address, and the signature of the defendant, and they must be filed with the court to officially add them as a party to the case. There are two types of Illinois Additional Defendant Signatures, Names, & addresses documents: the "Notice of Additional Defendant" and the "Affidavit of Additional Defendant". The Notice of Additional Defendant is a form that must be filled out and signed by the defendant once they have been served with a summons and complaint. The Affidavit of Additional Defendant is a form that must be completed and signed by a defendant who has been added to a case after the initial summons and complaint have been served. Both forms must be filed with the court before a case can move forward.