The popular drama series, created by and starring Lena, followed the lives of four young women living in New York City and ran for six seasons until 2017, and although Jemima portrayed one of the central characters, she repeatedly tried to walk away during the early days of the show.
"She tried to quit like, three times," Lena explained on Dax Shepard's Armchair Expert podcast.
"She tried to quit after the first season, she tried to quit after the second season. Finally, after the fourth season, she was like, 'I think I'm staying,' and I was like, 'Good, 'cause you signed a contract for six years!' But she just didn't give a s**t."
Jemima actually had her first feature-length film role in Lena's independent project "Tiny Furniture" in 2010, but she only agreed to star in the movie as a favour to Dunham, because the writer/actress needed the emotional support of having her best friend onset.
"She's such a big part of everything I've ever done professionally, which is not an accident," Lena said. "I was like, 'You, come with me.' It made me feel like I could make a movie when she was there. It made me feel like I could make a show when she was there. It still makes me feel like I could do it."
Jemima, the daughter of former Bad Company and Free drummer Simon Kirke, took a step back from acting to pursue other creative interests after "Girls" wrapped, the childhood pals are still eager to reconnect onscreen in the future.
"Now I really wanna make more things with her in them, and I think we're figuring out what they are," Lena shared, "but she's also a painter, and she has two kids. She has a very rich life..."