Kate Hudson practices yoga on aeroplanes.
The 36-year-old actress - who is the face of her own fitness wear brand Fabletics - has insisted she's not one to spend hours in the gym and instead does what exercises she can while looking after her kids.
Explaining that she sometimes works on her strength and flexibility while thousands of feet above ground in an aeroplane, Kate said: "I do things that people would think look completely insane."
The 'How to Lose a Guy in 10 Days' star - who has sons Bingham, four, with ex-fiance Matt Bellamy and Ryder, 11, with ex-husband Chris Robinson - rubbished the idea that working mothers don't have the time or equipment to stay in shape as she often improvises with what's readily available to her.
She told Allure magazine: "People think you need two hours a day to do it, and that's bulls**t.
"If you work out 20 minutes a day in some way, you're going to see changes.
"I've had days where I have the kids - Ryder's on his bike, and I put Bing in a stroller - and I will run and sprint up hills."
The blonde beauty added that for her exercise is about much more than looking good.
She added: "It's brain chemistry."