755 ILCS 5/7-1

Foreign will admitted to probate.) A will signed by the testator when proved as provided in this Article may be admitted to probate in this State when (a) the will has been admitted to probate outside of this State or (b) the will was executed outside of this State in accordance with the law of this State, of the place where executed or of the testator's domicile at the time of its execution.