Los Angeles, California - Millie Bobby Brown has found her next beach read - and she wrote it herself!

The 19-year-old Stranger Things star shared a new snap to Instagram on Sunday, which saw her lounging under the sun in a white bikini as she dove into her "summer read."

But it wasn't just any average page-turner, the book is actually Nineteen Steps, Millie's debut novel, which is set to hit bookstores this fall.

Nineteen Steps draws inspiration from her own family history in a tale following 18-year-old Nellie, who lives in Bethnal Green amid World War II.

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"Inspired by my Nanny Ruth, this book is very personal and close to my heart. I grew up listening to stories about her time living through the war. I'm honored to keep her story alive," the Enola Holmes actor says in the book's description.

Last month, she revealed the book's final cover artwork, which is different from the early copy she's seen reading in the new photo.

Millie's fiancé, Jake Bongiovi, showed his support as he commented two red heart emojis and reshared her photo on his own Instagram story.

The historical fiction novel is also getting some significant buzz from prominent authors in the genre.

The Alice Network writer Kate Quinn said, "My inner history-loving teenage geek clapped her hands in ecstasy at the thought of a historical novel penned by Enola Holmes, and she wasn't disappointed."

Just one of Millie's many exciting upcoming projects, Nineteen Steps will be released on September 12.