Reese Witherspoon’s Son Calls Her This Bizarre Nickname—& Even She Doesn’t Know Why

Nicknames come from all kinds of places—childhood moments, inside jokes or sometimes just because someone couldn’t be bothered to say your full name. And thanks to a new viral trend making the rounds on social media, users (including a few celebs) are sharing the many names they go by and the backstories behind them.

Reese Witherspoon jumped in on the fun on May 7, posting a lighthearted video on Instagram where she listed the different names people call her. And while most of them make total sense, one in particular had me doing a double take.

“‘Morty’ to my youngest,” she wrote, casually adding, “No clue why.”

The 49-year-old actress shares 12-year-old Tennessee with her ex-husband Jim Toth. She also noted that her older children, Ava, 25, and Deacon, 21, whom she shares with ex Ryan Phillippe, simply call her “Mama.”

The Legally Blonde star ran through the rest of her nickname roster, too, including, “‘Reese’ to my fans, ‘Sister’ to my brother, ‘R Dubs’ to my friends, ‘Ladybug’ to my mother, ‘Pieces’ to my high school friends, ‘Miss Reese’ to my friends’ kids, ‘Mama’ to my older kids."

All this while casually sitting on her trailer steps in a pink sweater and glasses, because of course she was.