Section 2–502. [Execution of Wills.]
(a) Except as provided in subsection (b) and in sections 2–506 and 2–513, a will shall be:
(1) in writing;
(2) signed by the testator or in the testator's name by some other individual in the testator's conscious presence and by the testator's direction; and
(3) signed by at least 2 individuals, each of whom witnessed either the signing of the will as described in paragraph (2) or the testator's acknowledgment of that signature or acknowledgment of the will.
(b) Intent that the document constitute the testator's will can be established by extrinsic evidence.