"Orange Is the New Black" fans, remember that fantastic backstory episode for Sophia Burset, the transgender inmate played by Laverne Cox?

In the ep ("Lesbian Request Denied," the one directed by Jodie Foster), we learn that Sophia is married, that she has a son, and that her wife stuck by her through her gender-reassignment process. We also see Sophia before her surgery, when she was New York City fireman Marcus Burset, who boosted credit card numbers to finance the surgery.

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And the guy playing the presurgery Mr. Burset: Laverne Cox's twin brother, musician M. Lamar.

"Initially, [series creator Jenji Kohan] approached me and said that they would hire someone [to play Marcus]," Cox said. "She didn't — this is [the] amazing support I got on set — she's like, 'I don't want to traumatize you, by having you play a man again.' You know, because I tried to play one for many years in my real life, and unsuccessfully. But, I'm an actor. I can play this … I got this. I can do it.

"So … we talked about it, we did a hair and makeup test to get Sophia's looks throughout her transition together. One of those looks was her as [Marcus], as the firefighter, but Jodie didn't think I looked masculine enough to play [him]," Cox continued. "And so it was decided that someone would be hired. I did my best to butch it up, and it wasn't butch enough, apparently."

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The actress said that she and her brother, who isn't an actor, didn't actually get to work together on the show — they shot their scenes on different days — but sharing a role did make her "OITNB" experience more special.

"I love my brother so much … in so many ways, he's been my moral compass over the years. Like, I run things by him and he's … we're twins, so we've literally known each other our entire lives," she said, laughing. "And there's a wonderful bond that we share, and there's a tremendous amount of respect that we have for each other as artists and as human beings. So I'm really grateful that I got to share a little bit of this show and this moment with him."

My sister @Lavernecox and I photographed together for the first time in over a decade.I am the evil twin. pic.twitter.com/pIotPNyVuo — M Lamar (@M_Lamar) July 19, 2013

Cox, who created "TRANSform Me" and was the first African American transgender woman to appear in a reality show, with VH1's "I Want to Work for Diddy," has also guest-starred on "Law and Order," "Law and Order: SVU," and "Bored to Death," and she is a regular contributor to the Huffington Post, where she writes about transgender issues.

In a recent conference call, the actress said that she was inspired in 2007 by the performance of transgender actress Candis Cayne on the ABC drama "Dirty Sexy Money" and hopes that she and "OITNB" can serve as inspirations to everyone who isn't used to seeing such a diverse collection of female characters in a TV series.

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"Candis Cayne had, for me, what was a watershed moment on 'Dirty Sexy Money,' when she became the first trans woman to have a recurring role in a primetime series," Cox said. "That moment was such a huge inspiration for me, [and] I really believe I wouldn't be here if it weren't for her and for that show just deciding to cast a trans woman to play that part. That inspired me to get an agent. … I had been trying to have a substantial career as an actor for a long time, and I began to believe it was possible six years ago because of Candis Cayne.

"I just want to work, and do quality work, and 'Orange Is the New Black' has set the bar really high for that," she continued. "Wonderful scripts, wonderful directors… I think it's important for trans folks specifically, but for anyone, really, who's not seeing their stories told on television to see their stories told up there and see people like them on TV. The wonderful thing about our show is that it provides a platform for a lot of different women who we don't get to see and hear from a lot, to be able to tell their stories through these characters. As a trans actor, I know that's important. I know that visibility matters, and I'm super grateful for the opportunity. I take it all very seriously."