Let's face it, [movieperson id="233447"]Jessica Alba[/movieperson] is known for her sexy factor. No matter what role she's in, be it a superhero ("Fantastic Four"), a pharmaceutical sales rep (in the upcoming "Little Fockers") or an immigration officer (this week's "Machete"), Alba's addition to any cast turns up its heat.

Such is even the case with [article id="1646345"]Robert Rodriguez's "Spy Kids 4: All the Time in the World."[/article] When MTV News caught up with the actress and her director at the L.A. [article id="1646618"]premiere of "Machete"[/article] earlier this week, we asked them how her casting came to be.

"I was so inspired, seeing her on [the 'Machete'] set trying to be beautiful for the camera and yet having to [run off] to change her baby's diaper," Rodriguez explained. "I thought, 'You know what, that would be great as a spy mom, I've got to write that in.' "

And since Rodriguez is the writer/director/creator of the "Spy Kids" franchise, he did just that. "I wrote that into the script, based on her," he said of what will be his third film with Alba.

The 28-year-old actress/mom said she's most looking forward to working with Rodriguez again -- and to eating more of the director's specialty: homemade margherita pizza with jalapeños.

Moving forward, Rodriguez has yet to cast his new titular spy kids, the husband to Alba's spy wife/mom or the villain Time Keeper. Original "Spy Kids" Alexa Vega and Daryl Sabara, as well as their onscreen dad, Antonio Banderas, are expected to play supporting roles. Production is set to begin next month.

Check out everything we've got on "Machete."

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