Joseph Leo Bwarie can sing "Sherry," "Dawn" and all those other Four Seasons hits with the best of them, as anyone who saw the touring production of "Jersey Boys" in January can attest.

But what about the original guy, Frankie Valli? Those tunes were challenging to sing for a young man. How does he handle those soaring falsettos at 75?

"We've adjusted a few of the keys down, but it is really about practice and discipline," Valli says via e-mail. "You need to exercise your vocal muscles every day. I still sing every day."

Tomorrow and Wednesday nights, he'll do his vocal exercises at Heinz Hall, in his first local show in four years. His last trip was one night at the Palace Theatre in Greensburg. Now that "Jersey Boys," story of the rags-to-riches rise of the Four Seasons, is a Tony Award-winning franchise, it's two nights Downtown, the second one of which is sold out.

The most surprising thing about "Jersey Boys" is that, in an age so full of biopics and pop-based musical, it took so long for the Four Seasons story to be told. It's rife with intrigue, considering the group's hard-scrabble upbringing, early struggle for success, amazing and unlikely run of early hits, mob connections, late '60s decline and '70s comeback.

Valli says he's seen "Jersey Boys" so many times, "I lost count a long time ago. I was involved with developing the script so I wasn't surprised by anything. It is pretty close to the truth -- a little artistic license here and there, but pretty much that's the way it happened."

One of the true wonders of the Four Seasons' fortunes is that they countered the Fab Four from the British Invasion. So many late '50s/early '60s artists will tell you that the Beatles knocked them out of the water. The Four Seasons got there two years before the Beatles with "Sherry" in 1962. When the Beatles invaded with 19 hits in 1964 alone, Valli and the Four Seasons hung on with songs like "Dawn (Go Away)" and "Rag Doll" and continued to chart through early 1968, when things got all too weird and psychedelic for them.

"We just kept making the music we liked and the fans liked it, too," Valli says. "There was no real secret -- just making good music."

Both groups were nominated for Best New Artist Grammys -- two years apart. The Four Seasons lost to Robert Goulet in 1963 and the only other nod Valli got was a nomination for "Can't Take My Eyes Off You," a doo-wop departure in 1967. The Beatles won Best New Artist and went on to win another half-dozen Grammys while the band was together.

"We were never an industry group," Valli says. "We were a group of the working guy. The guys over in Vietnam, they were listening to our music."

Regardless of whatever treatment the Four Seasons received back then, they charted 31 hits and were joining the Beatles and Stones in the Rock and Roll Hall of Fame in 1990. Valli added nine more hits through the late '70s, including "My Eyes Adored You" and the title song from one of the original pop-rock musicals, "Grease."

He doesn't pick favorites among the notable songs Bob Gaudio wrote for him.

"Do you have kids?" he quips. "Which one do you like best?"

Rather than fade into obscurity on the oldies circuit, Valli turned up as a gangster who gets whacked on "The Sopranos," and then seemed very much alive when he freshened his discography in 2007 with "Romancing the '60s," his take on songs like "Call Me," "Spanish Harlem" and "What Becomes of the Broken Hearted."

Would he have done anything different? In a career with more than 100 million records sold, there's little need for regret.

"I don't believe in looking backward," he notes. "You work hard and do the best work you can. Then you move on."