By Clark Collis
Updated April 17, 2014 at 03:00 PM EDT

How gory is the new slasher movie Stage Fright? This gory: During her post-shoot ADR recording session, actress Minnie Driver wouldn’t even watch her own, very early demise. “It was too gruesome for her,” says director Jerome Sable.

So why did Driver agree to appear in the film in the first place? “She had been in The Phantom of the Opera, the film version [of the Andrew Lloyd Webber Broadway show],” explains Sable. “So I appealed to her on that level.”

Oh, right. There’s something we forgot to mention about Stage Fright. In addition to being a full-on, blood-soaked horror flick, the film is also a full-fledged, song-packed, musical.

Allie MacDonald (House at the End of the Street) stars as Camilla Swanson, the daughter of Driver’s murdered stage star. Years after the death of her mother Camilla is working as a cook at a summer theater camp whose latest production is The Haunting of the The Opera, the very musical Driver’s character had just finished performing when she was killed. After Camilla decides to audition for the show, it isn’t long before the number of performances is being matched by the number of slain performers.

“It was a very interesting process, doing a musical of this sort,” says Eli Batalion, who cowrote the film’s songs with Sable. “It was clearly not a Broadway revue. The songs were very organic to the story. The idea was not to do a sketch-comedy version of a horror film. It was to be very true to horror influences and certainly to bring out the gore fully. So people should be prepared for that.” Indeed, while Stage Fright is a comedy, its creators are keen to emphasize they took the horror elements of the film very seriously. “We basically took the approach that we are going to do more than one thing — in this case a musical-comedy and also a horror movie — [but] let’s not do any of that ‘lesser than,'” says Sable. “Let’s try to do both, and as they should be done. It was important to us to do our best with the gore and the horror scenes.”

Stage Fright also stars Big Love actor Douglas Smith as the brother of MacDonald’s character and rock legend Meat Loaf, who portrays the theater camp’s manager. “You have to really live him to believe him,” laughs Sable, of working with the Bat Out of Hell star. “When I first was about to start working with him, I was really concerned. I mean, I had seen his films, and I had also seen his stint on Celebrity Apprentice with Gary Busey, and I was wondering, ‘what’s he going to be like?’ But the truth is that Meat Loaf is amazing. He is the most passionate human being I have ever met and worked with. Once he gets into something, he goes all the way.”

Stage Fright is currently available to watch on iTunes and VOD. It opens theatrically on May 9. You can check out both the film’s trailer and an exclusive clip below.