The famous handshake between Frankie Valli, left, played by Joseph Leo Bwarie and Gaudio, played by Andrew Rannells, that led to a lifelong musical partnership. (Dancap Productions)Bob Gaudio, the songwriter behind Four Seasons hits such as Sherry and Big Girls Don't Cry, says he had a "gut instinct" that told him what songs would be a hit.

"It's really always been about gut instinct. You hear something, you see something…It gives you a rush," he told CBC cultural affairs show Q in an interview aired Monday.

He relied on that instinct in the creation of Jersey Boys, the musical that was a hit on Broadway in 2005 and has gone on to tour the world.

Jersey Boys is the story of Frankie Valli and the Four Seasons, the four lads from New Jersey who became a pop sensation on the basis of Gaudio's songs and Valli's distinctive high voice.

Gaudio, credited as composer for the show, backed up writers Marshall Brickman and Rick Elice in creating the story for the musical, which opened this weekend in Toronto to critical acclaim. Gaudio was in Toronto for the show's opening.

The veteran songwriter had recently caught the theatre bug and shows such as Smokey Joe's and Mamma Mia! were an inspiration, he said.

"I did a show called Peggy Sue that David Mirvish produced and it was done in London in the West End. That was my move into the theatre world," he said. "I fell in love with theatre — I fell in love with the energy and talent."

He convinced Valli, who is still singing and touring, to accept an offer of a musical based on the Four Seasons' story, rather than jumping at a TV offer.

Gaudio was keyboardist and songwriter for the Four Seasons, who included Valli, Nick Massi and Tommy DeVito, and he considers himself a guardian of the '60s boy band's legacy.

Bob Gaudio, keyboardist and songwriter for The Four Seasons, helped guide the story and wrote the music for Jersey Boys. (J.T. MacMillan photography/Dancap)"It was important to us, and particularly to me, to respect the audience that stayed with us all these years and fell in love with it and protect those memories," he said, emphasizing that the musical sought to capture the excitement of the group's music.

He was also conscious that the story of the boys from New Jersey was not well-known and that they seem to have been ignored by rock 'n' roll historians who turned their eyes to the rock sound of Led Zeppelin and the Beatles.

"We didn't get the kind of musical respect that some of the other bands of the time, the Beatles or the Beach Boys," he said.

"But one thing that stuck with me was the fact that [there was] not one acknowledgement to a record or a song we made in the Rolling Stone 500 edition of all-time great records. That one struck me — I don't know why."

Gaudio, who went on to write hits for Neil Diamond and Michael Jackson, said Valli agreed to tell their story, both the ups and the downs.

"This has paid off in spades, the fact that nobody really knows the story. When you see Jersey Boys, you're just in for a roller-coaster ride. There's lots of surprises," he said.

"We weren't glamour boys. We didn't have a following that would buy anything we did."

Gaudio wrote his first song, Short Shorts (a hit for the Royal Teens in 1958), at 15, but he said he had to fight to get the record company to agree to Can't Take My Eyes Off of You, a more mature song Valli wanted to record as a solo.

But he trusted his gut, and the song became his biggest hit.

Gaudio hasn't been disappointed with trusting his instincts over Jersey Boys, which is already drawing critical acclaim for its Toronto run.

"It's like living my life over, but with a 20-minute intermission," he said.

Jersey Boys has extended its Toronto run, which began Thursday, to Nov. 9.