It Ends With Us is starting off with a fiery reveal.

Blake Lively unveiled her latest hair transformation in the first photos of the upcoming movie adaptation of Colleen Hoover's best-selling novel.

Playing redheaded florist Lily Bloom, the actress stepped out with a new red 'do on the New York City set on May 15. Blake also rocked a bright fuchsia jacket over a pastel pink tee and long brown dress as she filmed on a sidewalk.

At one point in the day, the 35-year-old ditched her rose-colored tops to reveal her frock's halterneck detail for a scene with co-star Justin Baldoni, who plays her love interest Ryle Kincaid in addition to serving as the movie's director.

Blake's half-sister Robyn Lively was also spotted on set, though it's unclear if she was there visiting or as a part in the film.

Additional casting details for the highly anticipated flick has been very hush-hush, though it was announced last month that 1923 actor Brandon Sklenar will be playing Atlas Corrigan, Lily's old flame and childhood friend.

"Though coming from a complicated past, Lilly Bloom has always known the life she wants," the film's synopsis read at the time of the casting news. "While living in Boston, she meets neurosurgeon Ryle Kincaid and believes she may very well have found her soul mate. Soon, however, questions arise about their relationship, and to complicate matters her high school love interest, Atlas Corrigan, comes back into the picture, putting her relationship with Ryle in jeopardy." 

Neither Blake or Justin—who are also executive producers of the movie—have revealed who will be playing young Lily. However, Justin confirmed on April 19 that they have found their star following an extensive search that included an open casting call on social media.

"Thank you for being a part of the process, it was inspiring and all of the messages we received was just validation for why we're making this movie and why this movie is so important," he shared on Instagram. "We found our young Lily, we'll be announcing her soon."

First published in 2016, It Ends With Us gained popularity in recent years thanks to book lovers on TikTok. A sequel to the novel, titled It Starts with Us, was released last October.

This is not the first time Blake has been involved in bringing a book to life. Most notably, she played Serena van der Woodsen on the TV adaption of Cecily von Ziegesar's Gossip Girl novel series  from 2007 to 2012.

She also starred in 2018's A Simple Favor, which was based on the Darcey Bell book of the same name. A follow-up to the dark comedy is currently in development.

"I've actually read the script now," actress Courtney Lopez told E! News in January, "and it's so good."

Release dates for It Ends With Us and A Simple Favor's sequel have yet to be announced.

For now, see Blake's Lily Bloom-inspired fiery locks—as well as more celeb hair transformations—below.

The "Say So" singer showed off her dramatic hair transformation on Instagram, debuting bright purple hair and a spooky spider design on the back of her head.

The Kick-Ass actress debuted a fresh bob haircut, which she hasn't rocked in quite some time.

The American Idol judge revived her signature style of 2008 and revealed baby bangs in a June 20 Instagram.

The Vampire Diaries actress debuted fringe bangs for the Los Angeles premiere of her new film Out-Laws in June.

The "Vogue" singer debuted an edgy shag haircut on June 11.

The Dance Moms alum proved you can be blonde and brunette at the same time with her recent hair change.

The High School Musical alum has entered her French girl era, after showing off her new curtain bangs.

The New Girl alum ditched her trademark brown hair and blunt bangs for a sky-high blonde 'do for her upcoming appearance on the '80s-based Apple TV+ series Physical.

The "Over It" artist headed into summer with a shorter cut and new hair color, debuting her blonde bob to Instagram in May 2023.

The X-Men star kissed her shoulder-length hair goodbye and debuted a pixie cut on May 26.

While attending the Louis Vuitton cruise show in Italy on May 24, Emma debuted curtain bangs—a style she often rocked in the mid-2010s.

The Sweet Home Alabama actress debuted wispy fringe bangs in a stunning selfie. 

The Poosh founder went back to her brunette roots, debuting a new look. As she put it on Instagram, she's a "brunette4lyfe."

Amid her ongoing transformation journey, the Rob & Chyna alum debuted a short pixie cut with shaved sides.

On May 15, the pop star opted for a bold hair color, rocking jet-black hair.

Helen Mirren wowed at the 2023 Cannes Film Festival, as she debuted vibrant blue hair.

Playing Lily Bloom in the film adaptation of Colleen Hoover's It Ends With Us, the actress was seen with red hair while filming scenes in New York City on May 15, 2023.

The Star Wars actress debuted her newly shaved head on May 10, writing on Instagram, "Happy without hair!"

On April 24, the Tangled actress debuted a fresh cut and fringe bangs.

The "Flowers" singer unveiled a drastic hair change, going back to her brunette roots, at The Daily Front Row's Seventh Annual Fashion Los Angeles Awards.

The TikTok star debuted a drastic hair change at Coachella 2023, unveiling a blonde bob look.

Ava Phillippe, the daughter of Reese Witherspoon and Ryan Phillippe, debuted blunt bangs in an April 4 Instagram.

The Elvis star went bald for his role as Feyd-Rautha in Dune: Part Two.

The actress debuted a long bob on April 3 that's perfect for spring.

"@craphairclub hair is giving me so much joy still," the daughter of Nicole Kidman and Tom Cruise shared on Instagram March 29 along with a photo of her 'do. "Thank you."

The Pretty Woman star showed off her fringe bangs and fresh hair color on March 27.

The supermodel debuted a pixie haircut in a March 20 Instagram, while also sharing behind-the-scenes snapshots of her photoshoot with Pop magazine.

The star debuted a red hot new 'do in March 2023.

Kourtney debuted her biggest hair transformation in March 2023.

After reverting back from blonde to brunette, the SKIMS founder zhuzhed up her signature look with curtain bangs.

Sign up for E! Insider! Unlock exclusive content, custom alerts & more!