John Malkovich stars in "Opus," former journalist Mark Anthony Green's directorial debut.Malkovich plays a legendary pop star who reemerges after years out of the spotlight.The actor tells BI he has no idea why Green thought of him for the role.John Malkovich knows he isn't exactly the first person you'd think of to play a gyrating glam-rock icon decked out in a metallic suit and chunky heeled boots. But he was director Mark Anthony Green's first and only choice to play Alfred Moretti, the reclusive yet beloved fictional pop star at the center of his new film "Opus.""I wasn't sure why Mark Anthony thought of me," Malkovich told BI at the red carpet premiere of "Opus" at the Sundance Film Festival. "I wouldn't picture myself as a pop star, particularly."The satirical horror movie is a warning about the cult of celebrity, taken to the extreme. It stars Ayo Edebiri as Ariel Ecton, a scrappy young music journalist who's invited to Moretti's compound as he prepares to release a new album after 30 years in seclusion.Malkovich's eccentric artist has seemingly nefarious plans for the group he's invited to his estate, which also includes Ariel's dismissive editor Stan (Murray Bartlett), a talk-show host (Juliette Lewis), and an influencer (Stephanie Suganami). Malkovich plays Moretti in "Opus." A24 In addition to the hip-thrusting and occasional lap dancing, Malkovich also sings some of the film's original songs. Green tapped Grammy-winning artist and producer Nile Rodgers and Rodgers' frequent collaborator The-Dream to write three songs for the film, and a vocal producer who worked with Rihanna to help Malkovich record them."I'm a baritone at best. I hadn't really sung, except in an opera, for 40 years. We started with the ballad, and the engineer said, 'You've got it, just go up an octave, you can do it.' And it was an octave I hadn't sung in since I wanted to be in a boys choir at age 11," Malkovich said in in the film's press notes. "So it was quite challenging."