Millie Bobby Brown debuted her long brown hair extensions on Monday as she headed to promote her book Nineteen Steps, wearing two stylish ensembles.

THE Stranger Things The star, 19, looked effortlessly chic in a white ensemble as she left BBC Radio 2 after advertising his first novel.

Her first outing of the day saw Millie dressed in a white linen strapless top with matching linen pants.

The actress added a glamorous pair of white pumps to her outfit, accessorized with a Louis Vuitton square clutch and added a gold choker.

Millie looks incredibly stylish and showed off her slim physique in her timeless wardrobe choice.

Gorgeous: Millie Bobby Brown showed off her new long brown hair extensions and headed out to promote her new book Nineteen Steps in two stylish ensembles on Monday in London.

Stunning: The Stranger Things star, 19, looked effortlessly chic in a white ensemble as she left BBC Radio 2 after publicizing her debut novel

The newly engaged starusually known for her short bob, presented her new brown hair extensions for the occasion.

She added a white headband to her first outfit and swapped it for a brown one for her second outing.

Meanwhile, Millie cut another trendy display as she donned a brown leather ensemble and showed off her toned legs.

The actress wore her faux leather blazer and mini skirt with a pair of white heeled boots.

Millie looked happy and relaxed as she greeted photographers and fans before heading to the venue in Piccadilly.

Nineteen steps, which will be released on September 12 is a historical novel about a courageous 18-year-old woman called Nellie Morris who lives with her family in Bethnal Green, in the East End of London, while World War II rages around them.

When a tragic accident occurs during an air raid one night, the consequences are catastrophic and life will never be the same for Nellie.

“Writing Nineteen Steps was a really special project for me. The story is inspired by real events and my own family history,” she explained, showing a photo of her and her grandmother.

Stylish: The newly engaged star showed off her new brown hair extensions for the occasion

Glamour: Her first outing of the day saw Millie dressed in a white linen strapless top with matching linen pants.

Chic: The actress added a glamorous pair of white pumps to her outfit and accessorized it with a Louis Vuitton square clutch and a statement gold choker.

Incredible: She added a white headband to her first outfit and swapped it for a brown one for her second outing

Slim: The actress wore her faux leather blazer and mini skirt with a pair of white heeled boots

Busy: Millie looked happy and relaxed as she greeted fans before heading to the Piccadilly venue

Incredible: Nineteen Steps will be released on September 12

In a statement released via publisher William Morrow, the Screen Actors Guild Awards The winner revealed a few more details about her personal connection to the story, according to The Hollywood Reporter.

“Inspired by my nanny Ruth, this book is very personal and close to my heart.

“I grew up listening to stories about his life during the war. I am honored to keep his story alive.

Millie and her fiancé, Jake BongioviJon Bon Jovi’s 21-year-old son recently got engaged after two years of dating.

The star recently revealed she started planning her wedding and it was “so much fun” in a candid new interview.

The actress expressed her excitement about being engaged to Jacques and plan their wedding together in an interview with Everyday women’s clothing last month.

The star also spoke about her preference for keeping her life private, as she prefers to keep special moments to herself.

She said of her upcoming big day: “I can say the planning is moving forward. It’s so much fun. And it’s such an exciting time in my life.

Cute: It comes after Millie revealed she’s started planning her wedding to fiancé Jake Bongiovi, 21, and it’s ‘so fun’ in candid new interview

“I’m probably thinking about drawing the curtains, just because there are only so many moments in life that you only get once,” she said.

“And having everyone’s opinions and eyes on it just doesn’t feel natural to me,” she said of wedding planning.

“So I think it’s important to keep these things – these precious little moments in life – really close to your chest.”