-By Gregg Kilday, The Hollywood Reporter

CANNES, FRANCE Warren Cowan, one of Hollywood's most influential press agents who represented a who's who of A-list stars during a seven-decade career, has died of heart failure and cancer at Cedars-Sinai Medical Center in Los Angeles. He was 87.

New York native Cowan, who died Wednesday night, began working as a publicist while still at student at UCLA. One of his first clients was actress Linda Darnell. In 1950, he became a partner with Henry Rogers in the firm Rogers & Cowan, which grew to become the largest public relations agency in Los Angeles. In 1989, the Los Angeles Business Journal reported, Rogers & Cowan led its competition by posting $9.5 million in billings.

Its clients included such stars as Danny Kaye, Kirk Douglas, Frank Sinatra, Tony Curtis, Shirley MacLaine and Elton John.

Whenever he was asked who his favorite client was, the politic Cowan would reply, "The next one." Among his achievements, he masterminded the modern-day Oscar campaign by helping Joan Crawford win an Academy Award for Mildred Pierce got Paul McCartney into the Guinness Book of World Records as "the most prolific composer of all time" and represented Ronald Reagan when the future president was an actor and the host of General Electric Theater.

In 1988, Rogers & Cowan was sold to British conglomerate Shandwick, and six years later Cowan set up a new company, Warren Cowan & Associates. Even though many of the stars whose careers he guided had faded from the scene, he continued to introduce new personalities to Hollywood, including Italian actor Roberto Benigni, whom Cowan assisted in his successful quest for a best actor Oscar for "Life Is Beautiful."

Cowan is survived by wife Barbara Gilbert-Cowan, the mother of actors Melissa Gilbert, Sara Gilbert and Jonathan Gilbert; two daughters from previous marriages, Fox News Channel reporter Claudia Cowan (with actress Barbara Rush) and Bonnie Fleming; and four grandchildren.

A funeral will be held Sunday afternoon at Mount Sinai Memorial Park in Hollywood.