Actress Reese Witherspoon says she is fascinated by her friend Nicole Kidman's eating habits. She also reveals Kidman is like a little old lady.

Witherspoon has spent a lot of time working with Kidman in recent years after joining her as a co-producer and star of "Big Little Lies", and she says watching her friend eat is always immense fun, reports aceshowbiz.com.

"She carries around these little bags of snacks all day," Witherspoon explains, adding: "I make fun of her. She pours hot cocoa on her cappuccino but only eats the foam. She eats weird old lady candies like your grandma had in the candy dish."

Kidman says the butterscotch candies she gobbles remind her of her grandmother, but she insists there's a health reason behind them: "I have low blood sugar."

As Witherspoon dished the dirt on her friend's eating habits, Kidman returned the favour.

"I'll tell you Reese doesn't like anyone eating off her plate. I have kids so I'm constantly doing that with them, but not Reese," Kidman revealed, adding: "I had a brother who ate all my food, so I'm like, 'Don't eat my food!'"