Tamera Mowry-Housley Spills a 'Sweet' Memory of Babysitting 'Very Young' Olsen Twins with Sister Tia

NEW YORK, NEW YORK - MAY 06: Mary-Kate Olsen and Ashley Olsen attend The 2019 Met Gala Celebrating Camp: Notes on Fashion at Metropolitan Museum of Art on May 06, 2019 in New York City. (Photo by Matt Winkelmeyer/MG19/Getty Images for The Met Museum/Vogue)
NEW YORK, NEW YORK - MAY 06: Mary-Kate Olsen and Ashley Olsen attend The 2019 Met Gala Celebrating Camp: Notes on Fashion at Metropolitan Museum of Art on May 06, 2019 in New York City. (Photo by Matt Winkelmeyer/MG19/Getty Images for The Met Museum/Vogue)

getty (2) The Olsen Twins and Tamera Mowry-Housley

Tamera Mowry-Housley and twin sister Tia Mowry had a pretty busy schedule as the teen stars of Sister, Sister , but they did occasionally moonlight as babysitters to the stars — specifically Full House stars Mary-Kate and Ashley Olsen!

In her new memoir You Should Sit Down for This, Mowry-Housley takes readers through her life — from landing her breakout role to her stint as a talk show host on The Real. And in one special anecdote, she shares how the biggest twin actors of the '90s aligned as she and Tia watched over the Olsens.

RELATED: Tamera and Tia Mowry Found Strength as Twins Because 'We Always Had to Fight ... We Are Very Strong'

It all happened when the Mowrys were on the Full House set with their little brother Tahj — who starred in 14 episodes of the TGIF sitcom from 1991 to 1995 — for an episode called "The Devil Made Me Do It."

"It was just for a moment. It was half a day. It was so much fun. I forgot where the mom had to go, but I love the fact that she trusted my sister and I to take care of them," she recalls. "They had to have been, I want to say 7 or 8. They were very young. So sweet, so kind. I remember all they wanted was matzo ball soup."

RELATED VIDEO: Tia Mowry Talks Sister, Sister Reboot and Her Parenting Style

But that wasn't her last encounter with the twins. "We ran into them, I want to say, when they were young adults, like 20, 21," Mowry tells PEOPLE in this week's issue. "I couldn't tell them apart!"

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You Should Sit Down for This is out now.