The former Grey's Anatomy actress adopted daughter Naleigh from South Korea in 2009 with her husband Josh Kelley.
She revealed on The Ellen DeGeneres Show that she hopes her daughter will have plenty of siblings in the future.
"I used to want like six kids," she revealed. "We're thinking maybe like three to four kids. That would be my ideal."
DeGeneres jokingly replied: "That's still a lot."
Heigl responded: "That's still a lot, isn't it? Alright, maybe two."
The New Year's Eve star recently said that she and Kelley "work hard" on their marriage while managing their respective careers.
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Watch the trailer for New Year's Eve below: