Spanish tenor Placido Domingo on Friday won the first $1 million Birgit Nilsson Prize for his "unrivaled" contributions to the world of opera, the award foundation said.

The Swedish soprano picked Domingo as the winner of the inaugural award - billed as the biggest prize in classical music - before her death in 2005. Prize officials said the name was kept in a sealed envelope until Friday's announcement.

"She wanted to honor one of the greatest opera singers of all time, whose contributions to the world of opera and concert are unrivaled," Rutbert Reisch, president of the Birgit Nilsson foundation, said in a statement announcing the winner.

Domingo has performed in 130 different roles and is celebrating his 40th season at New York's Metropolitan Opera. The 68-year-old singer won worldwide acclaim outside the opera scene as a member of The Three Tenors, with Jose Carreras and the late Luciano Pavarotti.

Nilsson and Domingo sang together several times, starting at the Met in 1969 with a matinee production of "Tosca," the foundation said.

"Placido acquitted himself splendidly. He was an incredibly good Cavaradossi, his acting was superb - he was the part, he loved the part and on top there was gorgeous singing," Nilsson said afterward, according to the foundation.

Nilsson, considered one of the greatest Wagnerian sopranos, performed at the world's top opera houses during a career of almost 40 years. She died on Dec. 25, 2005, at age 87.

Toward the end of her career she decided to establish a prize to be awarded every second or third year for outstanding achievements in opera and concert. Subsequent winners will be decided by the foundation's council, which will take recommendations by a jury of prominent figures in classical music.

A prize ceremony is planned for later this year in Stockholm.