Georgia Code Title 24. Evidence § 24-4-405

(a) In all proceedings in which evidence of character or a trait of character of a person is admissible, proof shall be made by testimony as to reputation or by testimony in the form of an opinion.

(b) In proceedings in which character or a trait of character of a person is an essential element of a charge, claim, or defense or when an accused testifies to his or her own character, proof may also be made of specific instances of that person's conduct. The character of the accused, including specific instances of the accused's conduct, shall also be admissible in a presentencing hearing subject to the provisions of Code Section 17-10-2.

(c) On cross-examination, inquiry shall be allowable into relevant specific instances of conduct.