Laverne Cox is one of the most prominent trans actresses in Hollywood today, being at the forefront of trans rights advocacy with her career and activism.

The star, most recently seen in movie Promising Young Woman and Inventing Anna on Netflix, has an identical twin brother with who she has a sweet, supportive relationship.

Going by the stage name of M Lamar, Reginald Lamar Cox is a composer and performer that many fans of Orange Is The New Black have got to know in two episodes of the show. Laverne's twin played her character Sophia Burset in some pre-transition flashbacks, though he isn't an actor.

Laverne Cox's Twin Brother M Lamar Gave An Emotional Speech About Her

This year, Lamar appeared on ABC show Claim To Fame, where contestants with famous relatives are tasked to guess the famous relations of their co-stars. He participated under the pseudonym of X and was eliminated in the third episode.

Before leaving the show, Lamar gave a heartfelt speech on how his sister has blazed trails for other trans actresses and how much he is proud of her.

"I have so much respect for my sister. I've never really spoken about her, but since she's the reason why I'm here I want to say in front of the world, I love her so much," the musician shared about his Emmy-winning sibling.

"I think she is the most extraordinary person I've ever met. She has endured all kinds of insanity and continues to. She continues to stand with so much dignity and pride and go forward and be an inspiration for so many people," Lamar added.

Related: Why Laverne Cox Nearly Quit Acting For Good

He continued: "Her success is so much bigger than her. The number of Black trans actresses who are on the covers of magazines, who are starring in television shows, all of that did not exist before my sister. And I just want to thank her and praise her."

Laverne Cox Calls Herself "Blessed" For Her Brother's Support

For her part, Laverne took to her Instagram to share how touched she was by Lamar's words.

"I am an immensely blessed woman in a plethora of ways. One of the most important is that I have known my brother @lamar_m_lamar my entire life. I don't have words to express what his words here broadcast on @claimtofameabc last night mean to me. My brother's love, support and counsel are part of the reason I am who I am," she wrote after her brother's elimination.

"And this reaffirms for me that there is a God, a higher power, a blessed energy force bigger than us. Thank you M, my brilliant, talented, charismatic, visionary, revolutionary, N*gro Gothic (a term he coined. Get into it yuh!) genius twin sibling! Thank you God! #TransIsBeautiful #claimtofame #siblings #twins #UnconditionalLove."

How M Lamar Got To Play Pre-Transition Sophia On Orange Is The New Black

Lamar isn't an actor, but gladly accepted to play the role of pre-transition Sophia on Orange Is The New Black.

In Sophia's backstory scenes, it is revealed that she used to work as a firefighter. Her wife stuck with her during her transition, while her relationship with her son became strained.

In an interview, Cox revealed that she wasn't asked to play a man, but decided to give it a try anyway.

"[Creator Jenji Kohan] 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,'" she said in 2013 (via Yahoo! Entertainment).

Cox tried, but director Jodie Foster "didn't think I looked masculine enough to play [him]," so someone was to be hired. Lamar seemed like a natural choice for the role.

Related: OITNB Star Laverne Cox Chats To Trans Creators For Trans Awareness Week

"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," Laverne said, adding: "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."

Inside Laverne Cox And Lamar's Relationship

The bond between Laverne and Lamar is loving and caring, but also has room for them to roast each other from time to time — just like any other sibling duo.

On Conan on TBS in 2014, Laverne gave fans an insight into her relationship with her brother, who was less than impressed with his acting experience.

"He was on a radio show doing an interview and he was telling a story that he was on the subway once and someone came up to him and said, 'Are you Laverne Cox from Orange is the New Black?'" Laverne shared.

"And he told the guy interviewing him that I was offended when he told me the story that someone thought that I was a man because my brother is clearly a guy, and he said that he was offended that someone thought he was an actor," she continued.

Related: Is Laverne Cox's Character In Hulu Horror Bad Hair A Nod To OITNB's Sophia?

"That's my brother, I love him."

While we might not get to see Lamar in front of the camera again soon, we're sure the siblings will continue being each other's biggest fans.