Actress and possible robot Katie Holmes has a secret to keeping her thin figure. No, it doesn't involve anybody named Xenu.

Her celebrity weight loss ticket to svelt-ness?

Drum roll please ... diet and exercise!

Who would have guessed?

"I grew up in an environment full of athletes and unfortunately I'm not one of them. But my parents and I were always very healthy," the mom of Suri Cruise told Shape.

"We even go running on Thanksgiving - I mean, what family does that? It has to be before the big turkey dinner. My dad is really ambitious and makes us all go. Exercise is definitely important, but the long hours sometimes prevent me from being a good girl and getting my cardiovascular workout."

Well, it's hard to argue with that. All of that effort it must take to run and hide from a crazy Tom Cruise is sure to shed the extra pounds.