The actor and his best friend Greta Caruso co-wrote The Secret Society of Aunts and Uncles.

“That was Dan Santat,” Gyllenhaal tells EW of the Easter egg, with a laugh.

“He snuck that in before printing, and I didn’t approve that.

Jake Gyllenhaal attends Disney’s “Strange World” Premiere at El Capitan Theatre on November 15, 2022 in Los Angeles, California, The Secret Society of Aunts & Uncles Hardcover – Picture Book, September 5, 2023 by Jake Gyllenhaal (Author), Greta Caruso (Author), Dan Santat (Illustrator)

Jake Gyllenhaal; ‘The Secret Society of Aunts and Uncles’.Axelle/Bauer-Griffin/FilmMagic; Feiwel & Friends

I don’t know where that came from.”

So I guess that was Dan’s joke on me."

No one explained what it was or what the requirements were to them or to me.

So, we thought, wouldn’t it be interesting to write a book about it?

No, but there were many versions of the story.

He gets this call in the middle of the night going, “You are officially an uncle.”

That was the first idea that we had.

Throughout the process I pitched it to my nieces, but it was never tried on them first.

Where did you come up with this concept of the titular secret society?

Greta and I loved the bookThe Magic School Bus.

It was one of our favorite books as kids.

But we loved the idea of dropping down to the center of things.

Do you have things like that with your nieces?

We do stuff all the time.

We haven’t done the burp thing.

I mean, we’ve definitely burped, but not like to get all the burps out.

Was it not good to burp?

They dictate it; I am their personal chef.

Over the years, that’s been the most fun thing for both of us.

We eat whatever we want and I get to cook it.

So we all get enjoyment out of it.

But yeah, burping and farting are absolutely required on uncle time.

Do they have a favorite dish that you make?

It’s all over the place, but generally simple stuff.

There’s not a favorite.

The book is really about both.

I’m a nephew and I’m also an uncle.

My uncle Bob is my mom’s brother who’s not alive anymore.

He was a really wonderful influence.

But then also, my dad has five brothers and sisters.

My Uncle Max was always so playful and joked with me.

My nieces tell me what an uncle is about, how to be an uncle.

They get to define it.

Leo’s passion is dance in the story.

Why did you choose that hobby?

Well, there are two things.

One, my oldest niece, Ramona is a big dancer.

She loves dance and she’s a beautiful dancer.

And Uncle Mo is named after Ramona because Mo is her nickname.

Gloria is my other niece’s name, so that’s in there too.

It feels like a pure expression of oneself.

My uncle also introduced me to a lot of pop culture, likeStar Wars.

They’re deeply sophisticated and more sophisticated than me and cooler than me.

I didn’t really introduce them to things.

My girlfriend has great fashion sense, and so she introduces them to things.

They always love what she’s wearing and they spend a lot of time together.

But for me, no, I’m more taught by them than them by me.

Did it take you a minute to get the hang of being an uncle?

That’s really what the book is about.

I still falter and flail a bit in it.

I had this idea of what it was going to be.

But then you’re deeply connected.

It takes time to understand yourself and to really learn how to be open and alive with that.

Do you have a proudest moment as an uncle?

There are moments all the time.

My youngest niece is this incredible violinist.

They’re 16 and 11, and they give me hope for the future.

But it’s the small things that mean so much.

We have a million ideas, and we had to whittle them down into this one.

We would love to keep going and expanding it.

The process of writing the children’s book, particularly working with Dan, became very cinematic for me.

It is cinema in a way.

You’re exchanging ideas for imagery, you’re changing words for image.

And we worked like that.

So it feels actually animated to me already.

How else have you been spending your time during the strike?

Well, I am actively looking to get back on stage.

I love it so much.

But I’m spending time with family.

We’ve been reading and cooking.

And then, writing.

Honestly, I’d like to be telling my own stories and directing my own movies at some point.