Pregnant Blake Lively Kept News of Baby No. 4 'Very Quiet,' Says Source: 'Friends Were Surprised'

Blake Lively's pregnancy wasn't just news to her fans. When the actress first revealed her pregnancy Thursday at the 10th Annual Forbes Power Women's

Summit, many of her friends were also "surprised" by the news, as source tells PEOPLE exclusively. "Even her friends were surprised that she was pregnant again," the source

says. "She kept it very quiet." The insider also notes that Lively is a "really attentive mom." "Her kids are her first priority over everything," the source says.

"You never would think that Blake Lively, this superstar and beautiful woman would be this regular person who cooks dinner every night and takes care of the family, but she is

really wonderful with the kids." Lively shares daughters Betty, 3, Inez, 5, and James, 7 with husband Ryan Reynolds. Never miss a story — sign up for PEOPLE's free

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Reflects on Being a Dad to Three 'Wild' Girls: 'I'm Like Any Parent' During a discussion at Thursday's event, Lively talked about being a creative woman who is also a

businesswoman. "I just like to create. Whether that's baking or storytelling or businesses or humans, I just really like creating," she joked, laughing along with the

audience. Lively said that it's important for her kids to "see that you don't have to choose one or the other." "I don't need them to choose to be a businesswoman or

a mom. They can be both or neither, but I just want for them to see that anything is possible."