Joe Manganiello Recounts Great-Grandmother's Dramatic Escape During Armenian Genocide on Finding Your Roots

Joe Manganiello is sharing his great-grandmother's harrowing survival story from the Armenian Genocide.

In PEOPLE's exclusive look at Tuesday's Finding Your Roots episode, the Magic Mike actor shares the heartbreaking events that his great-grandmother previously endured.

"The Turks came into her home in 1915 under the guise of World War I and tried to enact the genocide that they had begun," he says. "They shot her husband dead, shot her. She laid on the ground, pretended that she was dead while seven other gunshots that went off, which were her seven children."

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By playing dead, his great-grandmother was able to evade suspicion from the intruders. "She laid there unmoving and the Turks left the house and left the eighth child, who was an infant in the crib, to starve to death, which is just the way that they did business," Manganiello, 46, explains.

The woman "strapped the baby onto her back" and fled.

"For people who don't know, there were these death marches where they would just handcuff, chain the Armenians together and march them out to the desert, and release the Kurds, give them military coats, horses and guns, to then go do what they wanted with their mortal enemies, the Armenians," he says. "She escaped that."

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PBS

While fleeing, Manganiello's great-grandmother had to swim across the Euphrates river. Upon making it to the other side, she discovered her youngest child had drowned on her back.

"She had a bullet in her still, and to my understanding, she lived in a cave with other refugees until she was picked up by German military," he says.

In an internment camp, Manganiello's great-grandma became pregnant by a German officer. "She gave birth to a very blonde, half-German child," the actor adds.

As in episodes past, Finding Your Roots uses DNA technology to reveal the ancestry of celebrities. The series promises some unexpected discoveries as they retrace stars' family trees.

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Manganiello's story will appear alongside that of former football tight end Tony Gonzalez on Tuesday at 8 p.m. ET on PBS.