By day, he's a thumb-breaking, kneecapping enforcer whose preferred tool of trade is a 40-ounce Louisville Slugger.

By night, he's an opera-loving, antique-collecting artist whose preferred tool of trade is a Winsor & Newton sable paintbrush.

If Furio, the bone-snapping -- and bone-grinding -- intimidator on "The Sopranos" is at all like Federico Castelluccio, the 35-year-old, pony-tailed actor who plays him, then the secret of the casting may be this: Both were born in Naples, Italy...and both have a passion for their work.

As it turns out, Castelluccio has two passions, painting and acting, and his love of both is the reason for his appearance today at West Orange's Pleasantdale Farm, owned by The Manor restaurant, to announce his participation in a charity event.

Castelluccio, at the invitation of Wade Knowles, proprietor of The Manor, has agreed to join the CowParade, a unique fund-raising event that was held several years ago in Zurich, Switzerland, and more recently in Chicago.

New Jersey's version of the CowParade will include 25 renowned artists -- Castelluccio among them -- who will paint or otherwise decorate 25 life-sized fiberglass cows. Once completed, the cows will be displayed throughout West Orange, from June 23 to Labor Day. In September, the cows will be auctioned off and all the proceeds donated to various charities, including the Kessler Institute and the Edison Museum for Children.

Castelluccio, who came to the U.S. when he was 3 and grew up in Paterson, was brought into the CowParade fold through a serendipitously staged scene for an episode of "The Sopranos." It was the Tony-goes-to-Naples show in which the character of Furio is introduced, and an establishing shot was filmed at Pleasantdale Farm. After a day of shooting, Castelluccio told Knowles how much he admired the restaurateur's collection of paintings, which hang throughout The Manor. When Castelluccio later sent Knowles a copy of the February 1999 issue of American Artist magazine featuring a profile of Castelluccio and some of his work, Knowles knew he had to enlist the actor-artist in the charity event.

"When he told me about the CowParade I was a little confused," says Castelluccio, two of whose paintings were recently displayed in an art show at the prestigious Yoshi Gallery in Manhattan. "I thought I had to do a painting of a cow. Then when he told me what it was for, I thought it was beautiful -- and fun -- and I wanted to give something back."

Castelluccio has indeed had a lot to be thankful for lately. His art career has grown in leaps and bounds since he graduated from Passaic County Tech in 1982 and received a scholarship to the School of Visual Arts in New York City. But in his second career, he's been an itinerant actor for the past decade, appearing in everything from the New Jersey Shakespeare Festival to daytime soaps.

"I got a call for the first season of 'The Sopranos' to read for (the part of) the New York boss," says Castelluccio, who still lives in North Jersey. "I loved the show, but I knew I was totally wrong for the part and I didn't get a call back. Then (last summer) my agent called with the part of Furio. When I read it, I knew it was for me. I felt so good doing the audition. You don't need a critic to know when you're on, and I knew it, and they knew it, too."

Castelluccio, of course, got the part and has since appeared in eight episodes of "The Sopranos." He expects his character to return next season, as well.

"Unequivocally, no doubt about it, this has been a huge break," says Castelluccio, whose warm and articulate style of speech belies his goombah, broken-English character on the hit HBO show. "After the second episode that I appeared in, people were already asking me for my autograph. I can't step outside without someone shouting 'Hey, Furio.'... I figure every bad guy has to have a likable side. The New Jersey fans are incredible."

Incredulous is how most of those fans would probably react to the news that their favorite mob muscleman is not only an oil painter, but a renowned oil miniaturist. (He's also a beloved uncle to five nieces and nephews: "I can't squeeze them or kiss them hard enough," he says.)

"Five years ago I was commissioned to do a mural and I went to London to do research for the style of painting they wanted," says Castelluccio, who has already named his fiberglass cow "COWravaggio," after the 17th century naturalist painter Michelangelo Merisi da Caravaggio. "But what I really fell in love with was the Queen's Collection of Miniatures at the National Portrait Gallery. I was so impressed, and I decided that's what I wanted to do."

So after finishing up his all-expenses-plus-commission $60,000 mural, Castelluccio began to focus, in earnest, on much smaller sights. Actually, on canvases no larger than 2 by 3 inches. Castelluccio's oils -- mostly landscapes and portraits -- are painted on stretched canvas or wood, take no less than four weeks to finish, and sell, on average, for about $2,800. Buyers come from all over the United States, and all over the world, including Italy and Peru.

If you ask Castelluccio whether he considers himself a painter or an actor, he is quick to answer:

"I'm a painter first. I'm both actually. I have two professions. Acting is an art. There's a truth that has to come from inside. You have to find it where it begins. And it's the same whether it's painting or acting."

Fortunately or unfortunately, acting has temporarily taken hold of Castelluccio's life. Since "The Sopranos" wrapped for the season, he's been filming an independent action-drama, "Fire," which will be going to all the major film festivals this year, and in a few weeks he will start work on his next theatrical release titled "Made," co-starring Vince Vaughn and Peter Falk. (And yes, he gets to play an ambitious mobster again.) But the surge in the acting opportunities has meant less time in front of the easel.

"I haven't picked up a brush in a while," says Castelluccio forlornly, before remembering something and brightening: "Except for the cow, of course."