Angelina Jolie took on one of the most challenging roles of her career in Netflix‘s new biopic Maria, which documents the life of famed opera singer Maria Callas. Of course, being a film about a singer, one of the most important aspects of the role was the vocal performance. Jolie is seen singing throughout the movie, and fans have been wondering whether the Oscar-winning actress actually sang for real or whether she was lip-syncing. It turns out to be a bit of both, with Jolie’s voice mixed with Callas’ vocals. Director Pablo Larraín told IndieWire that Jolie’s singing was mixed with Callas’ voice in post-production, “So sometimes you hear 1 percent of Angelina’s voice, sometimes it’s 5 percent, sometimes it’s forty percent, in a couple of times, not very often, but it does happen, you listen to sixty percent or seventy percent of Angelina’s voice.