((a)) ** .—** An employee of the Department is performing official duty during the period with respect to which the employee is testifying in an official capacity in front of either chamber of Congress, a committee of either chamber of Congress, or a joint or select committee of Congress.

((b)) ** .—** The Secretary shall provide travel expenses, including per diem in lieu of subsistence, in accordance with applicable provisions under subchapter I of chapter 57 of title 5, to any employee of the Department of Veterans Affairs performing official duty described under subsection (a).