Director Lynn Shelton, who helmed movies Humpday and Your Sister’s Sister and episodes of shows including GLOW and Little Fires Everywhere, has died at the age of 54.

Shelton died in Los Angeles on Friday (May 15) of a previously unidentified blood disorder.

Marc Maron, her partner and creative collaborator, confirmed her death in a statement. “I have some awful news. Lynn passed away last night. She collapsed yesterday morning after having been ill for a week. There was a previously unknown, underlying condition. It was not COVID-19. The doctors could not save her. They tried. Hard.

“I loved her very much as I know many of you did as well. It’s devastating. I am leveled, heartbroken and in complete shock and don’t really know how to move forward in this moment. I needed you all to know. I don’t know some of you. Some I do. I’m just trying to let the people who were important to her know.”

He continued: “She was a beautiful, kind, loving, charismatic artist. Her spirit was pure joy. She made me happy. I made her happy. We were happy. I made her laugh all the time. We laughed a lot. We were starting a life together. I really can’t believe what is happening. This is a horrendous, sad loss.”

Shelton began her career as an editor, before making her directorial debut in 2006 with We Go Way Back. She went on to help popularise mumblecore in the late noughties with Humpday and Your Sister’s Sister.

The filmmaker also worked extensively in TV, directing episodes of shows including Mad Men, The Good Place, The Mindy Project, Master Of None, Love, Fresh Off The Boat, and GLOW. She most recently worked on four episodes of the Reese Witherspoon and Kerry Washington-starring Little Fires Everywhere, one episode of Apple TV’s The Morning Show, and Maron’s latest special, End Times Fun.

Shelton is survived by her parents Wendy and Alan Roedell, David “Mac” Shelton and Frauke Rynd, her ex-husband Kevin Seal and their son Milo, her brothers David Shelton and Robert Rynd, and her sister Tanya Rynd.

Actor Mark Duplass, who starred in both Humpday and Your Sister’s Sister, paid tribute to Shelton on Twitter. “We lost our dear friend Lynn Shelton,” he wrote. “We made so many things together. I wish we had made more. Her boundless creative energy and infectious spirit were unrivaled. She made me better. We butted heads, made up, laughed, pushed each other. Like family. What a deep loss.”

Mindy Kaling wrote on Twitter: “Lynn Shelton loved actors and we loved her back. She was a dream on set. Her lovely, sunny energy was infectious and actors always drifted to video village between takes to be around her. She had such a quiet power and I will miss her. Rest In Peace, Lynn. Love you.”

Director Ava DuVernay added: “Lynn Shelton changed my life when she handed me the Directing Award at Sundance in 2012. She announced my name with pride. Handed it to me with love. Rooted for me long after. I can’t believe I’m typing this. Rest In Peace, Beauty. Thank you for your films. And for your kindness.”

See those and more tributes below.

We lost our dear friend Lynn Shelton. We made so many things together. I wish we had made more. Her boundless creative energy and infectious spirit were unrivaled. She made me better. We butted heads, made up, laughed, pushed each other. Like family. What a deep loss. pic.twitter.com/LcowmbGqum

— Mark Duplass (@MarkDuplass) May 16, 2020

Lynn Shelton loved actors and we loved her back. She was a dream on set. Her lovely, sunny energy was infectious and actors always drifted to video village between takes to be around her. She had such a quiet power and I will miss her. Rest In Peace, Lynn. Love you. pic.twitter.com/jGvbSV3fN1

— Mindy Kaling (@mindykaling) May 16, 2020

Lynn Shelton changed my life when she handed me the Directing Award at Sundance in 2012. She announced my name with pride. Handed it to me with love. Rooted for me long after. I can’t believe I’m typing this. Rest In Peace, Beauty. Thank you for your films. And for your kindness. pic.twitter.com/KySqgIdqQd

— Ava DuVernay (@ava) May 16, 2020

Oh no. RIP to the truly masterful Lynn Shelton. https://t.co/BdNcNliII9

— Alex Winter ? (@Winter) May 16, 2020

I loved Lynn Shelton's work so much. All her characters are so real and nuanced, and funny, and I wanted to work with her so badly. What a talent. This is such sad news.

— Abbi Jacobson (@abbijacobson) May 16, 2020

Devastating news. I was lucky enough to play a small role in a Lynn Shelton film & she treated her cast & crew like a family. I learned about directing from watching her. The kindness with which she treated people. The room she left for spontaneity. We've lost a great one. ?♥️ https://t.co/vzMwhL0yic

— Mike Birbiglia (@birbigs) May 16, 2020

Devastating news. I was lucky enough to play a small role in a Lynn Shelton film & she treated her cast & crew like a family. I learned about directing from watching her. The kindness with which she treated people. The room she left for spontaneity. We've lost a great one. ?♥️ https://t.co/vzMwhL0yic

— Mike Birbiglia (@birbigs) May 16, 2020

Lynn Shelton was one of the wonderful advisors I had the Sundance Labs. I am so sad and in such shock to hear the news of her passing. Her work and her mentorship was deeply affecting to me. Love to her friends and family. RIP, Lynn.

— Nia DaCosta (@NiaDaCosta) May 16, 2020