The actor, who shares Wyatt, 6, and Dimitri, 4, with husband Ashton Kutcher, made the admission during an appearance on The Ellen DeGeneres Show on Wednesday.
Mila explained that a few months ago, she and Ashton received an offer to star in a Cheeto's Super Bowl commercial and jumped at the opportunity to escape quarantine for two days.
"It was the peak of the pandemic. It made no sense logically. It may have been the worst time do it," she said. "We were so quarantined, and I was dying to get out of the house."
"I was literally like, 'I don't care. I need to get out of this house!' I looked at it as a two-day vacation. I was like, 'We're getting out. We're going to shoot this thing, and we're going to get away from our children,'" she continued. "I'm a horrible mom."
"I love my kids very much, but they're like dogs," Mila went on. "They can sniff you out. They know your smell. They know what room you're hiding in. You can't get away from them. You just can't. They're just there!"
However, Mila revealed that despite initially being excited to make a break for it, she ended up feeling "vulnerable" and "uncomfortable" shooting in the midst of the pandemic, and was consumed by worry that she'd catch COVID.
"It's really uncomfortable because you're not wearing a mask. You're really exposed," she explained. "You feel like a lemming — no one's allowed to talk to you. You're not allowed to talk to anybody. You don't know what anyone looks like. It's a bizarre experience."
"I was then pretty convinced I had COVID," she added. "I was like, 'Oh, this is how I get COVID. This is it.' But, needless to say, knock on wood, that didn't happen."
This isn't the first time Mila has spoken out about the effect of the pandemic on her family. Just last week, the actor revealed that the Kutchers are incredibly "codependent," and quarantine has only fed that dynamic.
"Our whole family is already codependent, so this pandemic just feeds into our entire codependency," Mila told Entertainment Tonight. "My husband and I were codependent for, like, eight years."
"In this pandemic, our kids are like, 'Where are you going?' And I'm like, 'The bathroom,'" she added. "We haven't left each other. We're in the house. They've forgotten that we have to go out of the house."