Transgender activist Nicole Maines is joining the cast of The CW's Supergirl.

Maines, 20, will play Nia Nal, also known as Dreamer, a young transgender woman with the power to see the future. Nia Nal will be television's first transgender superhero.

The casting announcement was made Saturday at San Diego Comic-Con.

Maines was the plaintiff in Doe v. Clenchy, which was decided by the Maine Supreme Judicial Court in June 2013. The case marked the first time that a state court ruled it unlawful to deny transgender students access to the bathroom of their choice.

Maines has previously appeared on the USA Network drama Royal Pains and the HBO documentary The Trans List.

“We've had representation on television for a while, but it hasn't been the right kind of representation,” Maines told Variety, referring to non-transgender actors playing transgender roles.

“Now, it's very hopeful and relieving to watch creators and writers and directors and casting offices stepping up to put trans people in trans roles, so we can portray ourselves and we can start to disprove some of those stereotypes about us.”

“I'm beyond thrilled to be able to do that in Supergirl,” she added.