Naomi Watts put fake blood on her children to help them understand her work.
The actress - who has sons Alexander, three, and Samuel, 22 months, with actor Live Schreiber - says the boys are still confused by their parents' careers so they try their best to make what they do accessible to the kids.
She explained: "They think we work in trailers - they think that's our office.
"The movie I'm filming now is about the 2004 tsunami. There was a lot of discussion with the boys that mummy's going to have 'owies' and they're just pretend. But you don't want them to be traumatized.
"By the end, Samuel was saying, 'Where are your owies?' So we put some fake blood on them. It worries me a little bit - it's not normal by any stretch of the imagination - but that's our job, and you have to try to make them understand it."
The 42-year-old star also revealed she has learned to slow down and not worry so much about her work since becoming a mother.
She added to Australia's Daily Telegraph newspaper: "I don't put in the same blood, sweat and tears.
"I want to think of myself as someone with a great work ethic - and I'm very committed to what I do - but I don't work as often as I used to. I used to take work home with me and stay up all night, brooding on how the scene went that day and how the next day would go. Now, the minute I walk in the door, it's finished; it's all about the kids. There's nothing like your children to pull you into the moment.
"Every day, something blows you away. You can wake up tired, after not having enough sleep, and your kid will say something brilliant that knocks you sideways."