Reese Witherspoon says she doesn't quite know how her youngest son came up with his nickname for her. In a social media post Wednesday, Witherspoon revealed her 12-year-old son Tennessee Toth calls her "Morty." The actress shared the video as part of a social media trend revealing what the people in her life call her.

Just call Reese Witherspoon "Morty" from now on. In a Wednesday, May 7, Instagram post detailing the different names she goes by, Witherspoon, 49, shared the interesting fact that her youngest child,

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.