Lena Dunham began writing her memoir a month after leaving rehab

The Girls creator - who entered a treatment facility in 2018 - wrote on Instagram: "When I first began this book, I'd been out of rehab for 30 days. I was in the cloud of delirium that comes with new sobriety - the world was suddenly so LOUD, and I thought that meant I knew what I was hearing. If you'd told me then that the writing process would take me through the next seven years, I probably would have ripped up my contract and chucked my laptop in the tub.

"Throughout my twenties, writing was all pure immediacy. I'd have an experience, put some version of it through the filter of fantasy, and it would be playing on television six months later. Writing was how I processed as it was happening. I hadn't lived enough life to deal with it in retrospect. I didn't understand the value of time - to heal us, to make sense of where we've been, to actually change the patterns we keep replaying in our work and our art.

"The gift this book has given me over the last seven years was that it was always there. No matter what changed - my location, my body, my mind - there was a constant: this place I could go to try and make sense of the story.

"When we finally set a publication date for Famesick, I felt something like grief. One of my steadiest companions was leaving. But it's time."

Lena recently promised to tell "the truth and nothing but the truth" in her upcoming memoir.

The actress - who entered rehab for an addiction to benzodiazepines - told People: "It took a long time to have the perspective to tell this story with honesty, humility and the appropriate dose of humour.

"I have been supported at every step of the way by my longtime editor, who encouraged me to tell the truth and nothing but the truth, so help me God."