'This Is Us': Mandy Moore Teases Big Revelations Ahead About Jack In Vietnam & More (Exclusive)

"This Is Us" star and Garnier brand ambassador Mandy Moore sits exclusively with Access and teases what's ahead for her hit drama. With Jack's experience in Vietnam being slowly uncovered, will Rebecca be able to help Kevin in his quest for more information? What about the woman with the necklace in Jack's photo? Plus, Mandy shares why she loves being considered a signature brunette! "This Is Us" airs Tuesdays at 9/8c on NBC.