The star's relationship with his nieces inspired his new children's book, 'The Secret Society of Aunts and Uncles'
“I would love to have a family, and if it's anything like the family that my sister's raised and has cultivated, I would be proud,” he tells PEOPLE in this week’s issue.
The memories he’s made with his nieces Ramona, 16, and Gloria, 11, ultimately inspired Gyllenhaal’s new children’s book The Secret Society of Aunts and Uncles (on sale Sept. 5), which encourages adults to loosen up, lean into the ice cream and live in the moment.
“My mother (director and screenwriter Naomi Foner) always told me that if you want to learn about any subject, start in the children's section and then work your way to the more complicated aspects of it because the most difficult thing to do is to explain something simply,” he says.
Written with his childhood friend Greta Caruso, the whimsical tale unpacks what Gyllenhaal, 42, has learned through “one of the most important relationships in my life” with his nieces, he says. But shining any sort of spotlight on the girls initially gave him pause.
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“I was a bit nervous because their privacy is so important to me,” he says. “But they were so excited that there was a book and really moved. And also my sister was too, which really meant a lot to me. I sent her drafts to read and she cried at all of them. She's a tough audience. So it's a book also about my sister and my brother-in-law (Peter Sarsgaard), who've raised two incredible girls. “
As Uncle Jake, one of his favorite things is to cook for his nieces. “I call up and I'm like, 'Okay, I'm coming over. What do you want to eat for dinner? I'll cook anything you want. I'm your personal chef,'" he says. The star is also excited about a trip to France in the works for Ramona: "We spend a lot of time in Paris, and so my big gift to her was a trip there together."
He and Maggie remain close, from supporting each other on the red carpet to developing projects together behind the scenes. “We talk all the time and we rely on each other,” says Gyllenhaal, adding that he would “adore” to be directed by his sister. “She sees me for all of my stuff and she can bring that out in me. And I think I would show her vulnerability, probably, I haven't been able to do on screen and otherwise, because I trust her and I love her.”
Gyllenhaal has been dating French model Jeanne Cadieu for five years and says their relationship — which included a stint living next-door to his godmother Jamie Lee Curtis during the pandemic — has evolved over time.
“It's all about growing together and listening and being open. It's really not much different from any relationship when it works,” says Gyllenhaal.
For more about Gyllenhaal, pick up this week's issue of PEOPLE.
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