A SINGER DOING a Frank Sinatra tribute in an Atlantic City casino? Stop the freakin' presses, right?

Not so fast. That isn't just any singer paying homage to the showbiz immortal on the stage of Resorts Casino Hotel's Superstar Theater. As a matter of fact, Brandon Tomasello, whose "Sing, Swing, Sinatra" program runs through Feb. 16, is unlike any performer in the almost 34-year-history of legal gambling in Atlantic City. After all, up until now, entertainers headlining extended-run presentations in AyCee have been old enough to gamble. Not so with Tomasello, who clocks in at a mere 19 years.

While most musically inclined people his age are far more interested in rap, country or pop, Tomasello - who grew up in his grandparents' home at 12th and Porter in South Philly and attended the Philadelphia Performing Arts Charter School - pretty much only has eyes (or, more to the point, ears) for the music of the Great American Songbook as rendered by his hero, Francis Albert Sinatra. So why would a modern teen be so compelled by the 14-years-gone crooner that his wardrobe accessories and jewelry (an orange pocket hankie, a pinkie ring engraved with his family name) are based on those of his hero's?

"I didn't find Sinatra, Sinatra found me," insisted Tomasello as he sat in his dressing room - the same one Ol' Blue Eyes once used - after a recent performance.

Truth be told, Tomasello, whose rail-thin build definitely recalls Sinatra's when the latter was the heartthrob of millions of 1940s bobby-soxers, simply couldn't hide from the sounds of Sinatra. "It's just because I grew up with him," he said of his intense interest in Sinatra. "He's like a family member. It was drilled into my head."

It wasn't that long ago Tomasello considered a career as, of all things, a funeral director. But once Stephen Garbesi, his best pal since third grade and the show's technical director (he appears as both Tomasello's DJ and onstage foil) heard him sing Sinatra a couple of years ago, the die was cast.

Tomasello is no stranger to Resorts. Casino co-owner/CEO Dennis Gomes was so impressed with Tomasello when he first heard him sing last summer that he invited him to be a regular attraction at the casino's Whiskey Bar. "When I first discovered Brandon singing, I was blown away by his talent and knew he was destined to be a star," said Gomes.

Another fan is entertainer Joe Piscopo, who knows a little something about performing Sinatra's songs. "I think the 'Old Man' would be proud," offered Piscopo. "The kid is so respectful of everything about the Sinatra name and family.

"Brandon's timing is impeccable and his vulnerability onstage is warm yet very Sinatraesque. I will tell [him] stories about Mr. S. [and] about the music of Mr. S., and he will study and hang on each word like a brilliant student."

At first, hearing such Sinatra signatures as "Fly Me to the Moon," "I've Got You Under My Skin" and "Summer Wind" doesn't really bring to mind the original, for Tomasello's voice is much higher than the burnished baritone for which Sinatra is best remembered. But in his earliest days, Sinatra's vocals were considerably higher.

Tomasello more than compensates for the vocal disparity by displaying an impressive feel for his subject's one-of-a-kind phrasing. And his easygoing stage presence and comfortable, self-deprecating between-song patter mark him as a natural entertainer, rather than simply someone with a strong set of pipes.

Interestingly, Tomasello admitted his fascination with Sinatra goes beyond his music to a specific character trait he shares with the music icon. He claimed that, "ever since I was little, I wanted to be in charge. I wanted to be the boss."

The youthful vocalist doesn't intend to forge a career as a Sinatra impersonator. Instead, he sees himself in the Michael Buble mold, a young singer keeping alive the prerock pop tradition but with a contemporary sensibility (the only non-Sinatra number in Tomasello's set is Buble's swinging take on Queen's "Crazy Little Thing Called Love").

But to hear him tell it, what he does onstage is secondary to simply being onstage.

"I have to be an entertainer," he proclaimed. "We just ended the show and I can't wait until 3:30 tomorrow to get back up there."

Resorts Casino Hotel, Boardwalk at North Carolina Avenue, Atlantic City, N.J., 8 p.m. tomorrow and Feb. 14; 3:30 and 8 p.m. Wednesday and Feb. 8 and 15; 3:30 p.m. Thursday and Feb. 9 and 16. $20, 800-736-1420, ticketmaster.com.