How Mom Life Has Changed for Shay Mitchell Since Welcoming Baby No. 2

Watch: Why Shay Mitchell Says Having 2 Kids Is "WILD"

When it comes to motherhood advice, Shay Mitchell can't keep a secret.

In fact, the Pretty Little Liars alum had plenty of life lessons to pass down while exclusively speaking to E! News at the Oct. 9 launch of her new BÉIS collaboration with model and fellow mom Elsa Hosk. Having welcomed her second child—a baby girl named Rome—with longtime partner Matte Babel earlier this year, the 35-year-old shared that things around the house have been pretty "wild" with two little ones under a single roof.

"Going from no kids to one kid is a lot easier than going from one kid to two kids," admitted Shay, who is also mom to 3-year-old daughter Atlas. "It's amazing, but it is a whole other ballgame."

As for Elsa, who shares 19-month-old daughter Tuulikki with boyfriend Tom Daly, having one kid is already a "big change" in her household. "You're going from being so independent and having all the time for yourself to zero," she explained, prompting Shay to chime in and quip, "Now just wait, imagine if you have two!"

And with Halloween just around the corner, Shay has been hard at work planning out costumes for her little ones. "I've ordered four depending on Atlas' moods," she sheepishly confessed, adding that Rome's outfit will likely coordinate with whichever costume her big sister chooses. "That's like my favorite thing to do." 

While Shay doesn't foresee her kids getting too involved in any of the scarier festivities this year due to their young ages, she hopes that they'll be able to bond over spooky season one day. "Depending on the decorations, it may be a little bit scary for a 3-year-old right now," she said. "Later on in the years, I think they'll appreciate Halloween more."

For now, Shay and Elsa are enjoying being what they call "modern parents" with their respective partners. When Elsa—who teamed up with Shay to create a line of mom-friendly bags and accessories, out on Oct. 17—pointed out how she hasn't tied the knot with the father of her child, Shay quipped, "There we go! We have something else in common!"

The Dollface actress also "100 percent" agreed with Elsa's view that having kids help cement a bond in a relationship, saying, "That's the biggest commitment."