Dr. Henry Louis Gates Jr., author and Alphonse Fletcher University Professor and Director of the Hutchins Center for African and African American Research at Harvard University, joins us to discuss season 4 of his PBS series “Finding Your Roots.” In each episode, Gates dives into the ancestry of a celebrity to learn about their family's origins, connections to famous/infamous people and surprising secrets are part of their family's past. Season 4 guests include Amy Schumer, Larry David, Bernie Sanders, Questlove, Lupita Nyong’o, Christopher Walken and Aziz Ansari. 

PBS' "Finding Your Roots" premieres Oct. 3 at 8 p.m.