The Australian actress gained stardom when she was cast in season three of Netflix's "Orange is the New Black".
"I was so nervous doing the red carpet that I basically skipped everybody because I was anxious, I kept spontaneously crying, I feel like I'm probably gonna do it now", she explained, before tearing up.
"I feel like the reason I kept getting so emotional is that growing up, watching TV, I never saw someone on TV that I could identify with, let alone a superhero, you know?"
The actress explained that she just found out she won the part of the lesbian superhero on Monday night, just before she was supposed to walk the red carpet for the premiere of "The Meg".
Rose's Batwoman casting came weeks after Supergirl picked transgender activist Nicole Maines to fill the series regular role of Nia Nal aka Dreamer, television's first transgender superhero. I kept thinking like what do I say, because everyone always says, 'So what have you got planned next?' And I kept thinking, either I'm going to put my foot in it and accidentally say something or I'm going to just start crying, and they're going to be like. she doesn't look so good.
"The Bat is out of the bag and I am beyond thrilled and honored. I feel like one motto led to another".
Rose will debut as Batwoman in this year's DC-CW crossover before spinning off into a solo pilot and potential series.
The story will focus on Kate Kane, a young woman who says exactly what she thinks, and is motivated by an ardent desire for justice.
But she has been openly gay in the comics since 2006 when she was reintroduced as a lesbian of Jewish descent. But don't call her a hero yet. The CW's next annual event is set to air in December 2018.