The Australian actress - who came out as a lesbian at the age of 12 - has been cast as Batwoman in the new TV series and Ruby is thrilled to have been handed the opportunity.
Explaining the significance of the move, she told 'The Tonight Show Starring Jimmy Fallon': "I found out that I got cast as Batwoman. It's a game changer."
Ruby, 32, admitted she's been overcome with emotion every time she's stopped to think about her latest casting.
She shared: "I kept spontaneously crying and I kind of feel like I'm going to do it now, so I'm just going to..."
Ruby then explained that her casting as Batwoman has reminded her of her own childhood experiences.
She said: "I think the reason I kept getting so emotional was that growing up watching TV, I never saw anyone on TV that I can identify with. Let alone a superhero, you know?
"And I've always had this saying ... well, not me, but Oscar Wilde ... which is be yourself because everyone else is taken. I've lived by that motto and the second motto when I came into the industry was, be the person you needed when you were younger.
"I feel like one motto led me to the other and, you know, I kept crying about it."
The character of Batwoman first appeared in comic books as a romantic interest for Batman.
But she has been openly gay in the comics since 2006, when she was reintroduced as a lesbian of Jewish descent.
The TV adaptation was announced in July and it's been confirmed the script is to be written by Caroline Dries.