She was Bing's pride and joy—loved, protected and chastely obedient. His standards were clear. Shortly before he died last year, Crosby told interviewer Barbara Walters that he would disown his only daughter, Mary Frances, if she ever lived with a man out of wedlock. "Daddy was 73 when he said that," says Mary, an actress now 19. "He was raised Irish Catholic and was from a totally different generation. I respected his wishes when he was alive, but that doesn't mean his standards are my standards. My life is an entirely different matter."

For more than a year, in fact, she has been living with Ebb Lottimer, 27, a struggling songwriter and sometime model. Though they say they will marry at sunset two days before Thanksgiving in a nonsectarian ceremony of their own design, their prenuptial living arrangement has seriously strained Mary's relationship with her mother, Kathryn, Bing's widow. "Mrs. Crosby is terribly upset about all this," says a family friend. "She feels that since her husband's feelings were such a matter of public record, the whole world watches her children for any hint of scandal or misconduct. She feels that her daughter is not handling this at all well."

Ebb and Mary ("Only my mother calls me Mary Frances") met two years ago after she and her two brothers had appeared with their parents in a family song-and-dance act in New York. Mary had become friendly with Barclay Lottimer, an actor, who suggested his brother Edmund phone her when she got back to California. "It was an intimidating thing to call Bing Crosby's daughter," Ebb recalls. "There were the usual assumptions that she would be spoiled and a snob. But she was exactly the opposite. After canceling each other about three times, we finally had that first date, and it was real intense."

Even more intimidating was Ebb's first meeting with Bing almost a year later at the Crosby home in Hillsborough, Calif. "I was apprehensive," says Ebb. "Mary ran upstairs, and I waited in the library until Mr. Crosby walked in. I introduced myself, and he looked at me and said, 'Uh-huh.' Then he went in, sat down and read his mail. He wasn't real courteous. When Mary came downstairs, I could have killed her."

Despite her father's coolness, Mary thinks that Bing liked Ebb, though he never knew the couple had become lovers. "Daddy never openly gave his approval of any man I dated," she says. "No man was good enough. Later my brother Harry was teasing me and said, 'Well, Daddy, what do you think of Mary's man?' Daddy thought for a second, then said, 'Well, frankly, I never trusted a man who wears a bracelet.' But I knew he was kidding." By the time Bing died, in October 1977, Ebb was spending five nights a week at her San Francisco apartment and she was spending weekends at his. Ten days after her father's death, they moved into a small mountaintop home in Malibu. "Out of respect for Daddy, I wouldn't have done anything that he really wouldn't have held with. But more than anything else, Daddy wanted me to be happy, and I am. I do what I need to do for me."

Kathryn Crosby, however, feels that her daughter is too young to be married. Mary denies it's a problem. "I tried the dating game for about two weeks in college," she explains. "I went out with different guys every single night. It was an incredible bore always doing the same things—going to the movies, going out to dinner, going dancing. It was all so much garbage and game playing." Adds Ebb: "Sure, I was bothered at the time. I was 25 and Mary had just turned 17. I had nightmares. I thought to myself, 'I can go to jail!' But then I realized that Mary is probably older than most people I know at 40. And there's just an electricity between us that everyone can see."

Mary's mother remains unpersuaded. She has no intention of going to the wedding, says a friend, "unless at the last minute she feels she must save face and protect the Crosby image." "In the beginning," concedes Ebb, "Kathryn was very, very warm and very, very open and gave us a lot of space. Now she's a lot more cautious." Nevertheless, he and Mary are going ahead with their plans, having set the wedding date with the advice of an astrologer friend ("We need all the help we can get," Mary says with a smile). Would Bing disapprove too? "Look," says Mary, "when Daddy was alive he wanted perfect children and he got them. But we're basically normal kids—we have feelings and we hurt and love. We're not perfect and that's okay now. We don't have to be anymore."