From PEOPLE Magazine Click to enlarge
"It's all your fault!" Beverly D'Angelo joked to boyfriend Al Pacino's father, Sal, after she found out last summer that she was expecting twins. Sal, after all, had set the precedent by siring Al's twin half sisters, Roberta and Paula, 48 years ago. Then, on Jan. 25, D'Angelo, 49, gave birth at L.A.'s Cedars-Sinai Medical Center to Sal's 9th and 10th grandkids. Conceived through in vitro fertilization, Anton and Olivia Pacino weighed in at just more than 5 lbs. each. Says Sal, 78: "We're thrilled!"

So are Pacino, 60, and actress D'Angelo, a couple since 1997. While the never-wed Pacino has a daughter, Julie, 11, from a relationship with acting teacher Jan Tarrant, 46, the children are the first for D'Angelo, who separated from Italian duke Lorenzo Salviati in 1984 after three years of marriage; the couple didn't divorce until 1995. "Al has been wanting a son for so long," says Sal's wife, Katherine Kovin-Pacino, 48. (Al's mother, Rose, died in 1962.) "Beverly is going to make a wonderful mom. She is the best thing that ever happened to Al."

Giving birth at 49 was no snap for D'Angelo, especially when she had pre-labor contractions toward the end of her pregnancy. Friend Chevy Chase, her husband in the National Lampoon's Vacation comedies, says, "Because she's not a young mother, she was a little nervous." But D'Angelo held out well past her Jan. 8 due date, says Kovin-Pacino. "She was very uncomfortable at the end, but she came through like a trouper."

The new parents—D'Angelo lives solo in L.A. but often spends time at Pacino's house outside New York City—have been ducking calls. "They really want time on their own," says Kovin-Pacino. Chase jokes that the twins should have been named after the kids in the Lampoon movies: "I was hoping I she'd name them Rusty and Audrey."