Zac Efron fans fawn over actor's transformation into charming necrophiliac serial killer Ted Bundy

Shedding his Disney star image after the success of High School Musical was never going to be easy but Zac Effron may have just pulled it off.

The Hollywood actor is showing off his versatility and embracing his dark side by portraying one of the world's most notorious killers on the big screen.

Extremely Wicked, Shockingly Evil and Vile will tell the story of rapist, killer and necrophiliac Ted Bundy, with Effron as the lead.

With shooting under way, Effron shared a behind-the-scenes snap of himself in character. In the black and white Instagram picture posted to his 32.8million followers, the 30-year-old heartthrob posed for Bundy's infamous 1975 mugshot wearing a white T-shirt and bootleg jeans. The caption read: "Meet Ted. #behindthescenes "

In a bizarre turn of events, scores of his fans flocked to the comments section to gush about his transformation, with many referring to Effron as his alter ego Bundy.

"I've never been attracted to a serial killer until now," one person said. Another joked: "Hi Ted, we love you."

A third said they had "died and gone to heaven! "

The fawning continued with one commentator writing: "OMG I KNOW WHAT MOVIE IS THIS ❤️❤️❤️❤️ @zacefron , I can't whait to see you as a bad guy hahahaha ."

Others praised him for taking on the gritty role and broadening his appeal. One said: "Looking FWD to c how u handle the role of Ted. Admiration.

Another added it was "great to see Zac's range in more serious roles".

A third: "not looking forward to seeing you portray such a creep :(You're way too hot to be portraying Ted Bundy. He was a less than average (physically), nerdy closet case. I feel as if your portrayal could be a fetishization of serial killers."

Bundy was executed in 1989 for his crimes. He confessed to murdering 30 women and girls in the 1970s but the true death toll may be higher.

Extremely Wicked, Shockingly Evil and Vile will be told from the perspective of his long-time girlfriend Elizabeth Kloepfer, played by Lily Collins. She refused to believe he was capable of the murders for a long time.

The project will be helmed by Oscar-nominated director Joe Berlinger best known for his documentaries Paradise Lost trilogy and Metallica: Some Kind of Monster.