With flashbulbs flashing, fans and photographers surrounding her, singer and Dynasty star Diahann Carroll might have been stepping out of her black, stretch limousine onto the streets of Hollywood rather than Harvard Square yesterday afternoon.

Twelve-year-old Jennifer Campbell squealed with delight, "Oh my God! Oh my God!" as her mother lifted her above the crowd to catch a glimpse of Carroll yesterday at the Coop, where she was signing copies of her autobiography.

Signing autographs seated at a table surrounded by copies of her book, "Diahann!" Hollywood actress Carroll greeted a crowd of 250 fans yesterday afternoon in the Coop book store.

"They inundated the book department and overflowed onto Palmer Street," said Coop Sales Promotion Director Charles R. Tieuli. He estimated the crowd at about two to three hundred.

"She was an absolute doll for us--an absolute doll," he said.

Carroll, who plays Dominique Devereau on the night-time soap opera "Dynasty," stayed longer than intended signing autographs because of the large, enthusiastic crowd there to greet her.

"I've seen women 18 years old who don't look half as good," an admirer said.

"What an extraordinarily beautiful woman--isn't she gorgeous?" said Boston resident Ann R. Cohen.

Tieuli said that Carroll went out of her way to be friendly and personal. "She talked to each person and signed special messages like Happy Birthday," he said.

After a flourish and a smile, Carroll was whisked to her black limousine and back to TV land. Disappointed fans who didn't make it to the Coop have a second chance this Wednesday at 9 p.m. on television.