But eventually, Kidman saw Grace’s coat as more than just a layer of clothing.

“I’m in the coat and then the coat became a part of me.

That’s what a filmmaker does,” Kidman says of director Susanne Bier.

The Undoing

Credit: HBO

“They choose visually how to express things, and the coat is iconic.

In a way, it is the through-line of the whole series.

It protects me but it’s also my identity.

It’s got so many layers to it.

It’s my barrier and my shield from the world, but it also envelops me.

It’s interesting how [Susanne] uses that.”

Word is still out on just how much Grace’s coat can protect her.

The Undoingairs Sundays at 9 p.m. ET/PT on HBO.