George Pimentel/WireImage; Isaac Brekken/AP
Will Ferrell played Nicole Kidman
's husband in 2005's Bewitched
– and if she needs parenting tips, he's available.
"For me, talk to your children, at least once a week," Ferrell, the father of sons Magnus, 4, and Mattias, 1, joked to PEOPLE at Tuesday's premiere of Step Brothers
"If you've got time, do it two or three times a week," he adds. "But otherwise, I find the times where I let weeks and weeks go by without talking to my children, that adds up."
Week-old news of Kidman's baby's birth was slow getting to Ferrell. Kidman's daughter, Sunday Rose, was born July 7.
"I actually didn't know that," Ferrell said, when asked about
the birth. "Congratulations, Nicole! Did she have a boy or girl? A daughter. That's great!"
Asked if Magnus and Mattias are aspiring funnymen like their father, Ferrell, 41, said straight-faced, "No, they're not funny. They're deadly serious."