In an exclusive sneak peek at Tuesday's episode of Finding Your Roots, Harris learns that his ancestors have been in America since 1618 – two years before the Mayflower touched down.
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Harris, 42, cannot stop saying, "Wow" as historian and host Henry Louis Gates Jr. delivers each new tidbits about one of Harris' ancestors and his death-defying journey from England to the New World.
Past episodes of the show have explored the ancestry of celebrities including Maya Rudolph and Shonda Rhimes.
Finding Your Roots with Henry Louis Gates Jr. airs Tuesdays (8 p.m. ET) on PBS.