Uncovering Chris Rock's Roots

One famous face to appear on the show is comedian Chris Rock. In his research, Dr. Gates reveals that Chris's great-great-grandfather, Julius Caesar Tinghman, served in the U.S. Colored Troops during the Civil War. Within just a few months, Dr. Gates says, Julius was promoted to the rank of corporal. By the time he died in 1917, Julius had gone from being a slave with no possessions to owning 65.5 acres of land.

"Even while it was going on, he was telling me, 'Your great-great-grandfather owned property,' and 'Your great-great-grandfather did all this stuff,' I thought I was being Punk'd. I really did," Chris jokes. "I thought Ashton Kutcher was going to come from behind something and go, 'You know your grandfather was nothing but a slave. You know he just mopped up for white people. Come on, we got you.'"