In a press release, Michigan Opera Theatre said that Norman had dropped out of the production for "personal reasons." But MOT general director David DiChiera told the Detroit Free Press that she had been dissatisfied with some aspects of the production, including costume design and stage direction.

"It's hard to know exactly what her issues were," he said. "For a superstar at this stage of her career, they probably have to do simply with her comfort level with the role."

While lacking the marquee power of Norman, Brown is a rising star in her own right. She won rapturous reviews for her appearance in the Metropolitan Opera's Aida last fall.

Margaret Garner is based on a true story of a runaway slave who sacrifices her children rather than see them returned to slavery—a story that also inspired Morrison's novel Beloved. The opera was co-commisioned by DOT, Cincinnati Opera, and OCP. The world-premiere production, which will be presented by all three companies, features mezzo-soprano Denyce Graves in the title role as well as baritones Rodney Gilfrey and Gregg Baker. Stefan Lano is the conductor; Kenny Leon directs.