The actor recently revealed he had a ticket to ride on one of Richard Branson's future flights to space, but sold it back to Virgin after his wife told him it wasn't a "smart family decision" to risk the trip's danger.
Now, Mila's six-year-old daughter, Wyatt, has developed a love of space too, and even has aspirations of becoming a qualified astronaut.
And while mum is happy to encourage her daughter to achieve her dreams, she realises how ironic it is to support Wyatt after telling her man to keep his feet on the ground.
"My daughter is in love with space," she tells People. "Right now, if you asked her what does she want to be when she grows up, she's going to tell you she wants to be an astronaut chef in space. That's what she wants to be. On the International Space Station, she wants to be the chef and an astronaut."
"The fact that I made my husband (not) go to space..., I was like, 'You can't tell her! Don't tell her that because she'll hate me!' She'd be like, 'Ma!' Because I'm so encouraging like, 'Yeah, baby, you can go to space. You could do anything you want to do'. Meanwhile, I'm like, 'You're not going to space!' "
The "Bad Moms" star, who also shares four-year-old son Dimitri with Ashton, recently admitted she regrets telling her spouse to sell his space travel ticket.
"I was also hormonal and I was like, 'You can't, you're going to die. The thing's going to explode and you're going to die - and you're going to leave me with the babies!' " she recalled. "I hate it. Also, I'm such a Star Trek fan. The fact that I didn't let him go into space was so selfish of me, but I was a new mom and I was like, 'You can't leave me and the babies."
"And so that's where that decision was made out of. I want everybody to know I probably would have let him to go to space now, but now it's too late."