Section 735 ILCS 5/2-406 - Bringing in new parties-Third-party proceedings(a) If a complete determination of a controversy cannot be had without the presence of other parties, the court may direct them to be brought in. If a person, not a party, has an interest or title which the judgment may affect, the court, on application, shall direct such person to be made a party.(b) Within the time for filing his or her answer or thereafter by leave of court, a defendant may by third-party complaint bring in as a defendant a person not a party to the action who is or may be liable to him or her for all or part of the plaintiff's claim against him or her. Subsequent pleadings shall be filed as in the case of a complaint and with like designation and effect. The third-party defendant may assert any defenses which he or she has to the third-party complaint or which the third-party plaintiff has to the plaintiff's claim and shall have the same right to file a counterclaim or third-party complaint as any other defendant. If the plaintiff desires to assert against the third-party defendant any claim which the plaintiff might have asserted against the third-party defendant had he or she been joined originally as a defendant, the plaintiff shall do so by an appropriate pleading. When a counterclaim is filed against a party, the party may in like manner proceed against third parties. Nothing herein applies to liability insurers.(c) An action is commenced against a new party by the filing of an appropriate pleading or the entry of an order naming him or her a party. Service of process shall be had upon a new party in like manner as is provided for service on a defendant.