Lena Dunham wears revealing shirt dress as she opens up about how running has transformed her body confidence

She's a multi-talented writer, director and actor with a hit show on HBO.

And Lena Dunham also showed her activist side as she stopped by the Sirius XM radio studio in New York on Monday.

The Girls showrunner threw a cute black jacket with scalloped edge over a loose beige and white patterned linen dress, and accessorized with a unique pin of US Supreme Court Justice Ruth Bader Ginsburg's face.

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Unique style: Girls showrunner Lena Dunham wore a cute linen dress paired with red shoes as she visited the Sirius XM studios in New York on Monday

The acclaimed writer went make-up free and wore her brown pixie cut brushed up off her face. 

She added pointed red ballet flats with a sweet bow for a pop of color. 

And the committed feminist, who is launching her new Lenny newsletter this autumn and is a proud supporter of Planned Parenthood, also sported a pin of Supreme Court Justice Ruth Bader Ginsburg on her lapel.

Justice Ginsburg has consistently supported abortion rights during Supreme Court court rulings.

Casual look: Dunham went make-up free and wore a cute black jacket with a statement accessory

Feminist fashion: Dunham shared a close-up of her Ruth Bader Ginsburg pin, featuring the face of the US Supreme Court Justice

Dunham shared a close up of the unique accessory with her fans on Instagram, writing 'RBG watchin' over me.'

In a new interview with ESPN, Dunham also opened up about how she's embraced exercise as a way to help her anxiety and understand her body on a whole new level.

In July, the 29-year-old posted a photo of herself running to Instagram, telling fans she was proud to be photographed running on the streets of New York.

'When I saw that picture, what would normally embarrass me, which is a shot of me in physical motion, made me feel really good. I'm an open person, but that was pretty vulnerable for me,' she told ESPN.  

Proud moment: The Girls writer shared with fans how this photograph made her feel proud because she looked like a real runner after a lifetime of 'laziness'

The actress revealed she was forced to learn to run properly for her role as Hannah Horvath on Girls, after her producing partner Jenni Konner wanted to show how the character was evolving by taking up exercise.

And after hiring a running coach, Dunham says she's learned to appreciate her body like never before.

'It was the last thing I wanted to do. When it became something that actually gave me pleasure, I was shocked. Also, endorphins are real,' she said.

'You run with someone for an hour, you feel pretty good. Running for an hour does not make you feel worse,' she said.

And her new confidence and appreciation for her body makes it easier to let go of body issues, which still hold so many women back, Dunham believes.

Multi-talented: Dunham writes, acts, produces and directs her HBO comedy Girls

And while Dunham said she's able to brush aside cruel comments about her body on social media, the pioneering show-runner said she's bothered that other women with her shape will take those comments to heart.

'Bottom line is, I'm 5-foot-3 and 150 pounds,' she said. 'That is literally, I think, statistically the average American female body.'

'So when trolls come to my page and they say all that s*** and other girls see it, those girls are getting an unrealistic picture of what femaleness looks like, and I just can't let that happen on my watch,' she vowed.

Cult hit: Dunham with costars Zosia Mamet, Jemima Kirke and Allison Williams at the Girls Season 2 premiere in New York in 2013

Taking a stand: The actress says mean comments about her appearance don't bother her, but that she worries other women with her body shape will take the 'fat' jibes to heart