Royals Kristen Stewart's Princess Diana Portrayal Called 'Incandescent' as 'Spencer' Premieres at Venice Film Festival Kristen Stewart said playing Princess Diana in Spencer made her feel "more free and alive ... taller, even" while hitting the red carpet for the film's debut at the Venice International Film Festival By Stephanie Petit Stephanie Petit Stephanie Petit is a Royals Writer and Reporter at PEOPLE. People Editorial Guidelines Published on September 3, 2021 01:01 PM Share Tweet Pin Email Kristen Stewart. Photo: Stephane Cardinale - Corbis/Corbis via Getty Kristen Stewart's hotly anticipated portrayal of Princess Diana has finally debuted, and it's already earning rave reviews. Spencer premiered on Friday at the 78th Venice International Film Festival, with the leading lady hitting the red carpet in a nightgown-inspired outfit. She paired the pale teal ensemble with lace trim and a black bow at the waist with white heels, sporting her blonde hair down and tousled. Stewart, 31, posed for photos with film director Pablo Larraín, who sported a classic tuxedo and black bow tie for the movie's debut. Princess Diana in Crisis — Breaking Down the Most Telling Shots from the New Spencer Trailer Ernesto Ruscio/Getty Earlier on Friday, the Twilight star rocked a completely different look for a photo call at the prestigious film festival. She opted to pull her hair back to fully show off a black Chanel romper. Chanel was also behind the strapless ballgown featured on the first official poster for Spencer. Vogue Paris reported that the famous house, for which Stewart is an ambassador, recreated a Spring/Summer 1988 Haute Couture show gown — an undertaking that took at least 1,034 hours of work (including 700 just for the intricate embroidery featuring gold and silver sequins forming floral patterns) for the film. Kristen Stewart. P. Lehman/Barcroft Media via Getty Early reviews for Spencer praise Stewart's performance as Princess Diana as she navigates a holiday with the royal family as her marriage to Prince Charles dissolves. The Hollywood Reporter called the actress "incandescent" in her role, while Variety called the portrayal transformative. "Kristen Stewart doesn't just do an impersonation (though on the level of impersonation she's superb). She transforms; she changes her aspect, her rhythm, her karma," Owen Gleiberman wrote for Variety. "Mostly, though, what we see in Stewart's Diana is a woman of natural-born elegance, with a luminosity that pours out of her, except that part of her is now driven to crush that radiance, because her life has become a wreck." Kristen Stewart. Pascal Le Segretain/Getty Even before the film's debut, Stewart was gaining Oscar buzz. Attendees at CinemaCon in Las Vegas were shown a tease trailer and a five-minute clip of the film last week, quickly gaining acclaim. Insider's Jason Guerrasio tweeted an image of Stewart dressed as Diana, writing, "Just saw footage of SPENCER. Kristen Stewart is going all out for that Oscar glory. And her Princess Di accent is spot on! #CinemaCon." Can't get enough of PEOPLE's Royals coverage? Sign up for our free Royals newsletter to get the latest updates on Kate Middleton, Meghan Markle and more! Stewart spoke about the physical aspect involved in transforming into Diana. "I took more pleasure in my physicality making this movie than I have on anything," she said a press conference Friday. "I felt more free and alive and able to move — and taller, even." The actress said even from watching videos and seeing photos of Diana, the late royal "sticks out like a sparkly house on fire." "There are some people endowed with an undeniable, penetrating energy," Stewart said. "The really sad thing about her is that as normal and casual and disarming in her air, immediately she also felt so isolated and lonely. She made everyone else feel accompanied and bolstered by this light and all she wanted was to have it back."