Hollywood’s darling director, Greta Gerwig, who’s directing a big-budget “Narnia” adaptation for Netflix, is drawing heat for reportedly seeking to cast the Oscar-winning actress Meryl Streep to play the male lion king Aslan, who in the cherished novels on which the movie is based was meant to represent Jesus.  

Opposition grew from reports that the “Barbie” director is in talks with Ms. Streep — the virulently anti-Trump actress who’s won three Oscars – to voice the character of Aslan, a talking lion who rules over Narnia and serves as a central figure in the series. 

The author of the “Narnia” books, C.S. Lewis, a devout Christian, said that Aslan is an incarnation of Christ — the messiah — in Narnia. Fans of the books — which first came out in 1950 — are concerned that putting a woman in the role dishonors the author’s vision and snubs the faith aspects of the book. 

In the 2005 adaptation, Aslan was voiced by the actor Liam Neeson, a Catholic who considered becoming a priest before he entered acting and who won an Academy Award for his role in “Schindler’s List.” 

The “Narnia” books have generated a strong religious fanbase given that it is chock-full of Christian symbolism and allegories. The famous Stone Table — spoiler alert — on which Aslan is sacrificed is believed to be a representation of the cross, and Aslan’s death and resurrection parallel Jesus rising from the dead. The evil White Witch, who has damned Narnia to an un-ending winter and turns men into stone, is viewed as an allegory for Satan, whose reign over earth is marked by sin. 

The official X account for a popular Narnia YouTube channel, Into the Wardrobe, derided the controversial casting as “nothing short of insane,” and “an assault on the fan base.” The account’s manager, Stuart Hunt, launched a Change.org petition to urge Ms. Gerwig “preserve the gender of Aslan” in the upcoming film. The campaign has received 1,320 signatures and counting. 

“Make no mistake, an altered Aslan is a false Aslan. A false Aslan is a false Narnia.  The integrity of the character must be preserved at all cost,” Mr. Hunt wrote. 

Signatories flooded the comment section of the campaign to express similar frustrations. “Please do not do this!!! Aslan is a representation of God, and the Bible clearly states that God is in a male form,” one fan, Norah, wrote. “Please leave Aslan as he was. There is no need to ‘improve’ or ‘modernize’ what is already a masterpiece,” lamented another Narnia enthusiast, Rachel. 

Beyond the religious critiques, some fans have voiced their disappointment with losing a complex and beloved male character.  “In today’s world—where so many influencers and prominent figures portray a toxic and false of view of masculinity— Aslan provides a meaningful picture of true healthy masculinity,” Mr. Hunt wrote in the petition. “Aslan is kind, gentle, compassionate, and selfless.  He is also wild, fierce, brave and strong.” 

Aslan as a character is famous for his kingly mane and lionesses, of course, don’t have manes. In the veldt, lion prides have strong gender roles, with the strongest male being, literally, “the alpha male.” The potential gender-swap raises the question of whether Ms. Gerwig will change Aslan’s character from a male lion to a lioness to match the female voice of Ms. Streep. Other options include digitally altering Ms. Streep’s voice to sound male or allowing Aslan to keep his mane but be presented as some kind of transgender cat. 

The film, which is on track to start shooting this year, is expected to focus on the sixth book, “The Magician’s Nephew,” which is actually a prequel to the series. Ms. Gerwig told Time magazine last year that she was “interested in embracing the paradox of the worlds that Lewis created, because that’s what’s so compelling about them.” 

The latest controversy comes as studios have run into trouble when modernizing adaptations of beloved older stories that don’t share the 2020s’ preoccupation with gender and racial identity. Disney’s expensive, live action revival of “Snow White” faced backlash for its “woke” approach, beginning with the casting of Latina actress, Rachel Zegler, as the film’s protagonist, “Snow White” and Ms. Zegler’s derogatory comments about the fairy tale and anti-Israel social media postings. Perhaps most damaging to the film was the studio’s decision to portray the Seven Dwarfs as computer generated characters, rather than real life little people. 

The live-action remake of the Brothers Grimm classic bombed at the box office, grossing only $69 million domestically and $145 million internationally on a production budget of $270 million — and millions more to market.

Netflix has not yet responded to the Sun’s request for comment.