It was a lavish party staged by CBS to help kick off the new television season, and the mansion in Palos Verdes outside Los Angeles was jammed with celebrities, good food and live music provided by a pianist.

But as Paul Sorvino recalled the evening, things began to drag around 11 p.m. "There were a lot of people standing around talking," he said. "I said, 'Let's make an Italian party out of it.'"

So Sorvino stepped up beside the pianist, turned on a microphone and sang. His is a rich, listenable voice -- he's sung in regional operatic productions. And while Pavarotti doesn't have to look over his shoulder, Sorvino definitely put a charge into the air.

"I'm not a drinker, but I guess I'd had one or two," said Sorvino. "That's all I needed. I didn't put a lampshade on my head, but I must have done 15 songs. I think the party needed that, don't you?"

True. But the more crucial question for Sorvino these days is whether the public will embrace him in the role of a veteran policeman undergoing a midcourse career change.

That's the premise of "The Oldest Rookie," starring Sorvino as Ike Porter, a policeman who, in his late 40s, decides to trade his desk job for a street beat and detective's badge.

Sorvino is the youngest in a group of middle-aged-and-older stars who've landed television series this season. With Angela Lansbury having shown you don't have to be young to carry a series, and with the nation's population skewing older all the time, television is banking on the idea that it can be cool not to be kid.

This season features the return of Dennis Weaver to series television as Dr. Buck James; Dale Robertson as J.J. Starbuck, William Conrad as the Fatman half of "Jake and the Fatman"; Jerry Orbach in "The Law and Harry McGraw." Richard Kiley heads the ensemble in "A Year in the Life," and Dabney Coleman openly grapples with the ordeal of turning 50 as "Slap" Maxwell.

"There's a shifting away from the young audience," said Sorvino, who's the kid in the group. "Harry is a little older than I am; the Fatman is much older."

"Rookie" attacks the aging process head-on, taking the character and the actor through tough physical activity.

"I saw a universal appeal in this character," said Sorvino. "There isn't a man who wouldn't love to get physical at age 48, to have another crack at bat.

"I'm an avid tennis player, and all my tennis friends say if I'd only started playing this game earlier, I'd be a terrific player now.

"My character had developed his mind and social skills and feels the hunter-adventurer side coming to the surface ... Most of us are seeking our own heroism, and for men, that means getting physical. Ike has a chance and takes it, and has different physical challenges to overcome."

So does Sorvino, who does many of the action sequences himself. "You need that in the 8 o'clock time slot," he said, "lots of running and jumping. About two days a week I've got knee pads and sneakers on."

Sorvino began the series with 255 pounds packed on his 6-foot-2 frame. In his private life, regular tennis keeps him fit. "Underneath this symbol of success," he said of his girth, "there's a well-conditioned man." By the time he has filmed the series' commitment of 13 shows, he expects to be 20 pounds lighter.

He also expects to be several weeks into the show's run before the series' audience appeal becomes clear. Ratings in the show's first two weeks varied from okay to poor on a night when another network was premiering new shows.

He's enthusiastic about the rapport on- and off-camera he feels for his young sidekick, played by D.W. Moffett.

"I'm a subtle actor and for the first time, I'm playng myself, and my style of acting is becoming the style of the show," said Sorvino. "That style of acting doesn't hit you in the face. It will take some time to develop a following."

Sorvino's own life has followed a number of courses. He grew up in Brooklyn listening to Enrico Caruso and Mario Lanza records, and by 15 was studying voice. At 20 he was doing summer stock, and at 23 he had won a scholarship to the American Musical and Dramatic Academy. Two years later he appeared on Broadway in "Bajour."

He was nominted for a Tony for his role in "That Championship Season," and he produced, directed and starred in the off-Broadway staging of "Marlon Brando Sat Right Here."

In television, he's done series work in "Bert D'Angelo, Superstar" and "We'll Get By," and on film, there've been "Reds," "Off the Wall," "I, the Jury," "Slow Dancing in the Big City," and "A Touch of Class," among others.

At one point, despairing of show business, he wrote advertising copy while continuing to take voice lessons. That was good preparation for writing a book, How to Become a Former Asthmatic, detailing how he brought his own ailment under control. He's now working on a diet and exercise book, Everything to Lose, with the "Rookie" experience no doubt adding a chapter or two.

His wife, daughters Mira and Amanda and son Michael live in New Jersey.

That was Mira in a recent episode of her father's series, playing Porter's visiting niece who expects to see him poised to become police chief rather than working as a beginner on the street.

Nepotism? Nah. "The part called for a Harvard sophomore, age 19," he said. "She's a Harvard junior, age 19." She read for the role like anyone else, and Sorvino said he told the staff to do him no favors.

"She's studying oriental languages and culture and has taken acting lessons and performed," he said. "She's had to turn down roles that called for nudity. I told her, Something better is coming.

"It would be immodest to say how bright she is, but what can I tell you?"