Lena Dunham has been an outspoken advocate of the lesbian, gay, bisexual and transgender (LGBT) community for years -- thanks, in part, to her gender non-conforming sister, Grace.

The 30-year-old "Girls" star is the co-producer of "Suited," a new HBO documentary about the Brooklyn-based tailoring company Bindle & Keep, which has specialized in designs for transgender and gender fluid customers. In a PrideSource interview about the release of the new documentary, Dunham opened up about how her sister's "radicalized approach to being a woman" has influenced her both personally and professionally.

"Even though I consider myself female and I have a more binary approach to my sexuality, I think that Grace's idea about expanding the definition of what 'she' can mean has really opened me up," Dunham said. "Before Grace became so deeply embedded in her identity, I think that I was still thinking of the world as... I accepted the idea of transness, but I felt like I didn't understand the idea of a person whose gender and sexuality could contain elements of everything that they'd seen."

Rommel Demano via Getty Images Dunham said her gender non-conforming sister, Grace, has influenced her both personally and professionally.

As for the documentary itself, Dunham noted, "This is about an aspect of queer life -- we spend so much time thinking about, and rightfully so, these huge issues like marriage equality, raising families, job discrimination; this is a much more seemingly mundane issue. For the queer community and members of the gender nonconforming community, it actually ripples to every part of their life."

In 2014, Dunham and her longtime boyfriend, singer-songwriter Jack Antonoff, pledged not to marry until Grace could legally do so, too. Now that same-sex marriage is legal in the U.S., Dunham said she and Antonoff have discussed how they would potentially incorporate their respective sisters into their future wedding ceremony.

"Jack and I have talked about it and we've always said that when we get married, we want our wedding party to just be our two sisters in tuxedos," she said. Jack has a straight sister [fashion designer Rachel Antonoff], I have a queer sister; they'd be our best men/women and we'd call it a day."