Billie Eilish shocks fans with transformation for ‘The Bell Jar’

Fans don’t even recognize Billie Eilish as she transforms for her upcoming role.

Paparazzi photos from the Toronto set of the psychological thriller movie based on Sylvia Plath’s “The Bell Jar” show a red-lipped Eilish looking a far cry from her pop star persona.

The period piece not only has all in the cast dressed in their 1950s best, but Eilish sports her dark brown hair cut to shoulder length and held back by a matching percher hat.

Eilish, 24, is set to play protagonist Esther Greenwood — the aspiring writer who sits at the heart of the 1963 novel.

In some of the behind-the-scenes snaps, Eilish wears a fitted short-sleeve knit in a cherry red so bright it perfectly matches her painted lips. In others, she’s styled in a waist-nipped blue button-front dress.

Her makeup is minimal save for her bold lipstick choice; her hair is parted at the side and she wears a pair of pearl earrings.

A Reddit thread quickly emerged among the “Bad Guy” singer’s fans to discuss the multi-hyphenate’s new look.

“It took me too long to realize it was her. I was like ‘wow that actor looks just like Billie Eilish’” wrote one commenter.

Another agreed, “She does NOT look like a pop star at all and one of the most challenging thing to do as an actor is disappearing into a role.”

More echoed the sentiment, adding, “Wouldn’t have recognized her” and “Based on these pictures alone, it’s very possible I could’ve watched this whole movie and not realized it was even her.”

As “The Bell Jar” novel is widely considered a semi-autobiographical book, much of the inspiration behind Eilish’s new look seems to come from photos of Plath herself.

Eilish is, of course, known for her wide variety of colorful hair over the years and penchant for baggy clothing, although she has deviated from the formula in recent years, experimenting with different styles.

This will be the singer’s feature film debut, though she previously expanded into acting in 2023, playing a cult leader in the Amazon Prime thriller series “Swarm.”

Carey Mulligan is set to star as Mrs. Greenwood in the film, which is currently filming and is expected to be released next year.