Tenn. Code Ann. § 3-3-118: Oaths of witnesses

(a) All such witnesses, when so subpoenaed, before giving their testimony before the bodies or committees subpoenaing them, shall take an oath or make affirmation as provided by law for witnesses appearing in a court of record of this state to give testimony in such court.

(b) The speaker of the senate, the speaker of the house of representatives, or a chair of a committee of the whole of either or both houses, or the chair or chair pro tem of any committee of either or both houses, is authorized and empowered to administer oaths or affirmations to witnesses appearing before any such committee.