Who Do You Think You Are? - Season 4 (2013)

Singer Kelly Clarkson explores her lineage and uncovers an ancestor deeply rooted in American history; she comes face-to-face with her 3x great grandfather's wartime bravery and sacrifice.

Actress Christina Applegate investigates her paternal grandmother - a stranger to her and her father. Uncovering dramatic details along the way, Christina gains insight into the life and hardships of the woman she and her father loved, but never knew.

Media mogul Chelsea Handler confronts a deep family secret: her Grandfather’s rumored Nazi past. As she dives into her family’s struggle to survive in a desperate time, the details uncovered will finally confirm or deny his affiliation to the dark regime.

Actress Zooey Deschanel searches for rumored abolitionists in her father’s Ouaker family background. Her journey takes her around Pennsylvania where she uncovers, and follows, the story of a remarkable ancestor who sacrificed everything for her beliefs.

In memory of his late father, actor Chris O’Donnell investigates the paternal side of his family and finds ancestors on the frontlines of American history. Chris explores a patriotic legacy and a family devotion that extends deeper than he ever imagined.