When actor Rami Malek was offered the role of late singer Freddie Mercury in the biopic Bohemian Rhapsody, it was a “gun-to-the-head” moment.

Sacha Baron Cohen, 46, departed the project after filming began in 2010, owing to creative differences and was replaced by the actor, 37.

He described it as one of the “scariest” career decisions he’s ever had to make in an interview with The Guardian.

Freddie Mercury’s life is portrayed in the Queen-produced biopic (Picture: Twentieth Century Fox)

When asked to play one of rock’s greatest frontmen, he said “I must do this.”

“[It’s] kind of a gun-to-the-head moment. What do you do? And I like to think if it’s a fight or flight situation, I’m going to fight.

“The scariest endeavours that I’ve chosen to take in my life have been the most fulfilling and rewarding. And this has proven to defend that equation.”

Malek also commented on whether the film will address Freddie Mercury’s battle with AIDS, which led to his death.

“What’s the nature of celebrating a life? Definitely not avoiding his death in any way, or what caused his death, which is the Aids virus. But I think if you don’t celebrate his life, and his struggles, and how complicated he was, and how transformative he was – and wallow instead in the sadness of what he endured and his ultimate death – then that could be a disservice to the profound, vibrant, radiant nature of such an indelible human being.”

Malek’s portrayal as Mercury has gotten positive reviews from film critics who have seen early screenings of the film before of its release.

Many have questioned if the biopic will erase Mercury’s sexual identity and skirt over his AIDS diagnosis, and the film has been dogged by controversy.

Meanwhile, Malek confessed last week that Bryan Singer and the original director had “creative differences” before he was fired from the movie.

On November 2, Bohemian Rhapsody will be released in theaters across the United States.