STOCKHOLM - The late Swedish soprano Birgit Nilsson left a rich secret when she died in 2005 -- her choice for the first winner of her $1-million music prize, tenor Placido Domingo.

Nilsson, a great admirer of the Spanish singer since they first performed together in 1969, chose him as inaugural winner of the biggest prize in classical music for his "unrivalled" contributions to the world of opera, the award foundation said Friday.

Domingo returned the admiration.

"Birgit personified musical excellence and that's why she was a role model for me even before we sang together," Domingo said Friday in a statement released in New York.

When he and Nilsson sang in "Turandot" at New York's Metropolitan Opera, Domingo said, "there were moments when I was so overwhelmed with admiration for her vocal abilities and power that I almost forgot to continue singing."

"To be honoured by such an esteemed colleague means everything to me," he said.

Officials of the Birgit Nilsson Foundation said Domingo's name had been kept secret for nearly a decade. The reasons for that were not given, but plans for the creation of her posthumous Birgit Nilsson Prize were under way long before she died Dec. 25, 2005, at age 87.

"She wanted to honour one of the greatest opera singers of all time, whose contributions to the world of opera and concert are unrivalled," foundation president Rutbert Reisch said in a statement announcing Domingo as the winner.

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

Domingo will receive the Birgit Nilsson Prize in a formal award ceremony later this year, the foundation said.

The first Nilsson-Domingo performance, in 1969, was a matinee production of "Tosca."

"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.

In July that year, at the Arena di Verona in Italy, the two sang their first "Turandot" and Nilsson said she had caught tonsillitis after Domingo's lingering kiss at the finale, her foundation said Friday.

"It was worth it, in order to sing with Placido Domingo" she said, "for he was born not just with a stunning voice but also with the great, rare gift of musicality, which you either have or you don't, and was also a charming, fantastic person. And, yes, all the high notes were in place!"

In her own career of almost 40 years, Nilsson performed at the world's top opera houses and was recognized as one of the greatest Wagnerian sopranos.

Toward the end of her career she decided to establish a foundation for a prize to be awarded every second or third year for outstanding achievements in opera and concert music.

Reisch told reporters that Nilsson had told him of the first award choice in the late 1990s. A few years later she sent him a sealed letter -- to be opened three years after her death -- but to his surprise the name was not included in the letter.

"In fact it was a personal letter and I guess she didn't find it necessary to repeat the name," he said, noting however that the soprano earlier "had clearly made up her mind on Placido Domingo."

Reisch described Nilsson and Domingo as similar in both style and personality. "That means impeccable musicianship, glorious voice and thorough professionalism. ... It's really a meeting of the minds."

Domingo was the only name that had been firmly decided on from the start, he said.

Subsequent winners will be decided by the foundation's council, which will take recommendations by a jury of prominent figures in classical music.

"She and I had a number of discussions and we came up with a half a dozen names that might potentially be candidates in the future, but that will be decided by the jury then and not by myself," he said.