SAN FRANCISCO, JULY 22 -- A Who's Who of classical musicians, including a tutu-wearing Mstislav Rostropovich, threw a 70th-birthday party today for Isaac Stern, as some 30,000 people turned out to pay tribute to one of the world's most famous violinists.

Flutist Jean-Pierre Rampal and violinist Jaime Laredo were among those who performed with the San Francisco Symphony in a free concert in the city where Stern began his career 55 years ago.

Rostropovich stole the show, dancing onto the stage wearing the heavy makeup of a ballerina, with wig and white tutu. The artistic director of the National Symphony Orchestra then played cello for a performance of Camille Saint-Saens's "Carnival of the Animals."

The piece was really a carnival of Stern's life, with the music interspersed with a narrative read by actor Gregory Peck.

"Isaac is America's first and foremost violin virtuoso," said Peck, "a major force in the musical lives of China, the United States and Israel -- a one-man irresistible cultural force."

President Bush sent a note saying, "Isaac Stern is truly an American treasure."

Stern was born July 21, 1920, in the Ukraine and came to the United States when he was 10 months old. He made his debut with the San Francisco Symphony at age 15.

"This is the most gallant gesture I have received this year, to be able to just sit and enjoy," said Stern, who did not perform at the outdoor concert. "This is one hell of a birthday party."