"Oh my God, it happened to me last night!" Romijn jokes in the August issue of Redbook.
The star of TNT's King & Maxwell was married to Full House star Stamos for six years until their divorce in March 2005. During their marriage, Romijn used the name Rebecca Romijn-Stamos.
But the former model has now been happily married to actor Jerry O'Connell for nearly six years, and the couple share 4-year-old twin girls Dolly and Charlie.
"We're each other's assistants," Romijn explains to the magazine of why they chose not to use a full-time nanny. "We pick up each other's slack. Whoever is less busy helps the busier one: 'Can you go pick this up for me?' or 'Can you book my flight?' That's what real life is. Once you start paying somebody else to do the grunt work, who are you?"
Even before giving birth, Romijn fully embraced motherhood -- including gaining weight while pregnant.
"I wasn't worried -- you've gotta feather that nest!" she jokes. "Afterward, I was nursing for six months. When you're a new mother, your body doesn't belong to you for a while. You have to check your vanity at the door."
Romijn also didn't fret about turning 40. "Aging has never been scary to me," she shares. "I've always admired my mom's lines -- she has a beautiful, laughter-filled face. I've always thought that was attractive."
For more from Rebecca, go to www.redbookmag.com/Rebecca and pick up the August issue of Redbook, on newsstands July 9.