Hilary Duff warns new parents about the '2-week' phenomenon

Hilary Duff, a mother of three, is sharing a warning for expectant parents.

“Don’t get fooled by the first two weeks because you have an angel baby. They just haven’t woken up yet,” Duff said during a July 29 appearance on “The Kelly Clarkson Show.”

“You have those friends who are like, ‘This baby is sleeping through the night,’” she continued. “Just wait two weeks. They don’t know they’ve entered the world yet.”

Dr. Sara Siddiqui, a pediatrician at Hassenfeld Children’s Hospital at NYU Langone, told TODAY Parents that what Duff described is "a common experience." The peak time for gassiness and fussiness is typically between three and five weeks.

Clarkson, who is mom of 8-year-old daughter, River, and 6-year-old son, Remington, said she was also tricked into thinking she got super easy kids.

“The first year, you’re like, ‘They’re the kindest, they’re so nice,’” Clarkson declared.

She then gestured with her hands to show that they've since turned into devils.

“Oh yeah, my friend will be like, ‘My daughter’s eating curry and green things,’” Duff replied.

“Enjoy it,” Clarkson said, noting that soon it will be “‘I hate this.’”

Duff shares daughters Banks, 3, and Mae, 16 months, with her husband, musician Matthew Koma. She is also mom of 10-year-old son, Luca, from her previous marriage to former professional hockey player, Mike Comrie.

Last month, Duff opened up to TODAY Parents about raising resilient children.

“I feel like everybody else right now — a little worn down and powerless, for sure, and like my voice doesn’t matter,” the “How I Met Your Father” star explained. “But I do know that in my house my voice does matter, and that is my purpose on this Earth right now — raising my kids to be good people; to be confident and kind people who have a well-rounded understanding of others and the world around them. I know that is my most important job and that’s where I have strength and power.”

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