Edgar Vincent, the longtime press representative and right-hand man to Placido Domingo and a host of other opera stars, died Thursday at a New York City hospital. He was 90.

A resident of New York, he died of a blood clot while recovering from hip-replacement surgery, said his professional partner, Patrick Farrell.

"It is difficult to lose such a collaborator, such a friend," Mr. Domingo, audibly shaken, said by telephone from Vienna, Va., where he had just given a concert.

"He was there at every moment," he added. "He was somebody who had the right words, always."

Mr. Domingo had known Mr. Vincent since 1965; they worked together for more than 25 years.

Mr. Vincent's roster of past clients reads like a "Who's Who" of 20th-century musical luminaries. In addition to Mr. Domingo, it includes the sopranos Birgit Nilsson and Beverly Sills, the basses Ezio Pinza and Samuel Ramey, the violinist Yehudi Menuhin, the conductor George Szell and many others.

In the 1940s and 1950s, these people were larger-than-life figures of glamour and mystery. Opening night at the Metropolitan Opera was a social event of national consequence.

Mr. Vincent mediated between his clients and the demands of the press with impeccable manners, Old World charm, a rapier wit and an underlying eye to practicalities.

When the soprano Lily Pons was appearing in the Midwest during a U.S. tour, Life magazine said it would be willing to run a photograph of her -- milking a cow. "She said she would in no way milk a cow," recounted Jack Mastroianni, who worked with Mr. Vincent and was the manager of Salvatore Licitra, Mirella Freni and many other opera stars. "And Edgar said, 'How about if you milked it in a full-length mink coat?' " Ms. Pons milked the cow; Life got the photo.

Mr. Vincent also advised the solidly built Wagnerian soprano Nilsson, who complained that the costumes for a 1965 "Salome" itched and that she was not going to be allowed to perform her own dance. (The Dance of the Seven Veils is supposed to be a seductive high point of Strauss' opera.)

Mr. Vincent, accurately surmising that the production team had failed to appreciate his star's physical endowments, suggested that she "show her gams."

Ms. Nilsson, who, although built like an icebox, had a great pair of legs, showed up the next day in a pair of black wool tights and ultimately got to do the dance herself. She died in 2005.

"His advice was always impeccable," Mr. Domingo said.

Edgar Vincent Julius Raffaelle Simone Pos was born March 13, 1918, in Hamburg, Germany, and raised in Holland, the son of an Italian opera singer and a dentist whose father was the governor of Dutch Guiana (now Suriname). As a boy, he was a passionate pianist who dreamed of a concert career, but in his teen years he realized that he was not going to be good enough to satisfy his own expectations and gave the instrument up.

He later pursued hopes of an acting career to Hollywood, where his mother had connections to Warner Bros. Pictures. Despite striking good looks (he sported a debonair '30s-style pencil mustache to the end of his life), he did not advance far beyond appearing in small, non-credited roles in a few movies (including the 1939 "Juarez").

He later attributed this in part to "an accent you could cut with a knife," according to Jane Scovell, who interviewed Mr. Vincent for her book-in-progress about Mr. Ramey.

Mr. Vincent was so intensely private that even his closest associates knew little of his history.

His first public relations job was with publicist Muriel Francis, who had met him as an actor but hired him for his knowledge of music and command of languages.

His first client was Mr. Pinza, then in rehearsal for a show called "South Pacific." The rest was history, for Mr. Pinza's career and for Mr. Vincent. When Ms. Francis retired, Mr. Vincent took over her firm, later working in partnership with Cynthia Robbins and, for the past 21 years, Mr. Farrell.