Portman on playing Celeste

The biggest part of the character was the writing, Portman said.

Sometimes shes really authentic, and sometimes shes totally fake.

Sometimes shes cruel, and sometimes shes gentle.

Vox LuxNatalie Portman

Credit: Neon

Sometimes shes performing, and sometimes shes being.

It was really remarkable reading it.

So I feel like that really provided a great rubric.

natalie-portman

Michael Kovac/Getty Images

Brady shot this entire movie in 22 days; I shot it in 10 days.

I stayed at this hotel where I went to every bar mitzvah growing up.

The guy at the door was like, I remember you from you were in your bat mitzvah dress.

Youre going home to your baby.

And I was like, No, I need to stay.

I need to be professional.

They were like, Youre going.

And they kind of kicked me off set.

Hes one of the kindest, most wonderful people I know, and a real major talent.

It was really lucky because this is the fourth film Ive been in with him.

Ive known him over the course of 20 years.

Weve never been like buddies, or like hanging out, but Ive worked with him many times.

We didnt rehearse, we just started working.

I really thought Brady was nuts.

I was like, Are you sure?

Youre gonna have me stand to next to the character that played me in the beginning?

But I trusted it because Brady was very convinced about it.

And I think its so powerful in the film.

I thought it would be too easy to make a mockery of these songs if they werent good.

It was basically a process of mixing and matching lyrics and choruses and verses to make the soundtrack.

Portman added, It was incredible when I received the script to have the Sia songs with it.

But it was clear from the beginning that it had this incredible music.

And getting to record it was really fun.