“It’s, like, in our prenuptial agreement.

If I ask him to do something, he has to be there to support me.”

Scarlett Johanssonjust taughtColin Jostan important lesson about reading the fine print.

Colin Jost and Scarlett Johansson

Colin Jost and Scarlett Johansson.Kristina Bumphrey/Getty

If I ask him to do something, he has to be there to support me."

As Fallon laughed, she added, “He has to be in every one of my films.”

They welcomed their first child together, son Cosmo, the following summer.

Johansson also has a daughter, Rose Dorothy, 9, from her prior marriage to Romain Dauriac.

Guaranteed cameos aren’t the only benefit of being married to a fellow performer.

Johansson went on to reveal another perk of their relationship: She always has apartner to run lines with.

Unfortunately, enlisting Jost to help her learn lines doesn’t always go the way she hopes it will.

“I run lines with him, which is great,” she told Fallon.

“You’d think that would be very convenient because you have a partner there to help you out.

You learn your lines for tomorrow or whatever.”

“He does, like, real serious…

He really commits to the line reading,” Johansson said.

“And it’s not always the performance I want it to be.”

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“Yeah, you don’t want any performance,” Fallon pointed out.

“Just read the lines, you’re not going for the Oscar here.”

Johansson agreed: “I’m just like, ‘Say the lines!’

I’ll just learn them myself.'”

He’s so funny and off-the-cuff and charming and great."

Fly Me to the Moonarrives in theaters July 12.

Watch Johansson discuss the film and her husbands cameo in the video above.