Plus: DC’s Legends of Tomorrow star Maisie Richardson-Sellers previews Charlie’s “life-changing” identity crisis.

CW worlds collide in this exclusive sneak peak atDC’s Legends of Tomorrow’s latest episode.

“It’s a little Easter egg for the audience,” says Richardson-Sellers about the quasi-crossover.

Legends of Tomorrow

Michael Courtney/The CW

We actually shot theSupernaturalstuff on Halloween as well, so we had a lot of fun with that.

It adds a little bit of lightness to what is a very, very dark story."

Below, EW chats with the star about Charlie’s twisted family, her fears, and more.

ENTERTAINMENT WEEKLY: How has learning Charlies real backstory changed your performance?

In my head, the thing I kept coming back to was tragedy.

It just kind of made sense.

Is she a Fate or is she a Legend at her core?

Its a life-changing moment when she realizes shes going to have to make this decision once and for all.

Did the backstory you came up with also include any kind of complicated family dynamic?

No, it wasnt as much family.

For me, it was more that she had been betrayed.

So we were exploring these different ideas of her potentially being connected to some kind of mythology.

The sibling thing I had never thought of.

The only way she could was by constantly changing who she was.

All of these different layers of loss kind of fed into the way she was.

I had anger as being the root of her nonchalant, Ill do whatever I want behavior.

How is Charlie feeling about reuniting with her sister Atropos in this episode?

They know her better than anyone.

Do you think theres any part of her that misses her sisters and that familial bond?

What will she have to do to them to end this?

And what will that feel like?

DC’s Legends of Tomorrowairs Tuesdays at 9 p.m. on The CW.