By Hayley Spencer
Updated Mar 03, 2015 @ 11:15 am
Lena Dunham
Credit: Kevin Mazur/WireImage

Girls creator Lena Dunham has taken time out from playing Hannah Horvath to work on a project close to her heart: a documentary following her relationship with her hero, illustrator Hilary Knight. It's Me, Hilary: The Man Who Drew Eloise debuts on HBO on March 23, and thanks to a newly issued trailer, we have a sneak peek.

Knight penned the drawings that accompany Kay Thompson's Eloise children's novels, which chronicle the adventures of a mischievous 6-year-old who lives in the Plaza Hotel with her nanny, turtle, and pug. So how did Dunham and Knight come to meet? Their friendship blossomed after he learned that she had an Eloise tattoo (located on her lower back).

"I’ve always been obsessed with Eloise," Dunham told InStyle at the 2015 Sundance Film Festival earlier this year. "And Hilary Knight found out about my tattoo and wrote me a letter and sent me some books and I made contact with him and went over to his house for dinner. And it became quickly apparent to me that there was some work of art needed to be made about his life and its eccentricities and complexities."

The rest, as they say, is history.

In the preview for the film, which is directed by Matt Wolf, Dunham explains that "Hilary’s work has had a more lasting impact on me than anything else." While plenty of kids' relate to the scrapes Eloise gets herself into, Dunham says they had a special significance for her growing up: "Eloise does what she wants, when she wants, so there’s a lot to relate to if you’re a sightly weird child."

Watch the full trailer below.

—With reporting by Angela Matusik