Millie Bobby Brown wowed fans on Sunday evening when she took to Instagram to celebrate her latest venture – her debut novel. The Stranger Things actress posted a photo of her reclining by the poolside while reading a proof of the new book, Nineteen Steps.

In the photo, Millie could be seen on a sun lounger wearing a white string Slate Swim bikini, as well as some silver jewelry and pink tinted sunglasses to accessorize. "My summer read," the 19-year-old captioned her picture along with some suitably summer-y and book-loving emojis.

"So excited to read this," responded one fan, while another person wrote in all caps: "SO PROUD!" Millie's health and beauty brand Florence by Mills also commented on the photo to share support for her latest business venture, writing: "Summer mode: activated."

Just as fans were invested in Millie's debut novel (which will be released to the public in September 2023), many also took the opportunity to compliment the Enola Holmes actress on her relaxed look. Hundreds of fans liked comments which said statements such as "Respect button for Millie," and "Millie fans [love heart emoji] button."

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Another wrote jokingly "Can Jake fight, I'm serious," in reference to Millie's fiancé Jake Bongiovi, who also commented lovingly on her post with two heart emojis – as he often does in reply to her social media photos.

Millie and Jake, 20, got engaged in April 2023, and announced the news via their Instagram pages. Writing in the caption to her announcement, which featured a black and white photo of the couple smiling and hugging following the special moment, the Godzilla vs Kong actress penned: "I've loved you three summers now, honey, I want 'em all," in reference to lyrics in Taylor Swift's song 'Lover'.

Jake later echoed his fiancée's post with his own, showing them together in several candid photos including one of them relaxing at a lakeside spot along with the caption "Forever." The pair are believed to have been together since around June 2021, and Millie's oval diamond engagement ring is estimated to be worth around $150,000.

The Hollywood star announced her book deal in March. "Inspired by my Nanny Ruth, this book is very personal and close to my heart," she told fans in a statement released at the time. The novel is, as previously mentioned, not her first departure from acting towards different creative opportunities.

Millie launched her vegan and cruelty free beauty brand Florence by Mills in August 2019, and has seen great success with the label which sells a variety of products including eyeliners, mascaras, mud masks, moisturisers and more. In May 2023, following her exciting news about her engagement to Jake, Millie revealed more excitement as she launched her Florence by Mills associated coffee brand and subscription service.

WATCH: Millie celebrates her coffee brand launch

In March 2023, the young entrepreneur announced a partnership with Essentia water – again via her Instagram – where she explained: "It’s been hard to keep this one under wraps but I’m SO excited to announce my new partnership with @essentiawater! If you know me well, you know that whether I’m on set or working on florence, Essentia is my go-to water that keeps me hydrated."

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