Bernie Sanders on the season 4 premiere of “Finding Your Roots.” Photo: Screenshot.

Vermont Senator Bernie Sanders recently choked up after he learned that one of his relatives died while fighting the Nazis during World War II.

The Jewish former Democratic presidential candidate discovered details about his ancestor during the taping of the new season of the PBS series “Finding Your Roots.” In a promotional video released on Thursday, in anticipation of the show’s season 4 premiere on Tuesday, the lawmaker was asked by the show’s host — Harvard professor and historian Henry Louis Gates, Jr. — how he felt upon hearing about his relative’s story.

“I’m proud of his courage and willingly going to his own death in order to protect innocent people,” Sanders replied. “I’m very, very proud to have a family member who showed that kind of courage and decency.”

“It’s one of the bravest acts I’ve heard of,” responded Gates, who has hosted the show since it first aired in 2012.

Sanders added that he had started his career in politics “to prevent a descent of humanity into this kind of disgusting behavior” displayed by the Nazis. He said, “How does it happen? How can people do this? And that’s the struggle that we’re all involved in. It just makes us realize how hard we have got to work to not to descent into this kind of barbarity and to create a world where people can love each other and to do so many wonderful things together. That’s what this reinforces in me.”

Other Jewish figures who will appear in the fourth season of “Finding Your Roots” include Larry David, Scarlett Johansson, Amy Schumer and Paul Rudd.

Watch the video below to see Bernie Sanders on “Finding Your Roots”: