Diehard fans of the Beatles who only want to see a strictly faithful impersonation might have been turned off by the second half of the Fab Four’s show at Lincoln Theater on Saturday night, where the group performed songs the original band never did in concert.

But this wasn’t supposed to be a concert. It was theater.

That became apparent when Ron “John Lennon” McNeil came out with the singer’s famous long hair, beard, white suit and white tennis shoes, sat down at a white piano and gave a heartwrenching talk about the late musician who was inexplicably shot to death by a fan in front of his New York apartment building in 1980.

As the members of the Fab Four are careful to do throughout their performances, despite doing their best to imitate the Beatles in every way possible, he respectfully referred to Lennon in third person.

“There was a man who wrote about peace and love,” McNeil said in Lennon’s voice from the piano bench, facing the audience. “You may remember him. He certainly was one of my heroes — not necessarily because of what he said, but because he had the guts to say it.”

At the end of his brief talk, which completely hushed the previously raucous packed house, McNeil captured the oft-overlooked humble side of Lennon.

“It’s all senseless, really, but it seems we kill off our heroes and we left Beatles in the world to carry on,” he said, chewing away at a piece of gum in Lennon fashion. “Look, I’m no bloody genius up here, but I think we’ve got things the wrong way ’round. I’d like to dedicate this next song to anybody out there who still believes in peace, love and freedom.”

He then sang Lennon’s biggest solo hit, “Imagine,” with Gavin “George Harrison” Pring playing the strings on a synthesizer off to the side .

It wasn’t what the Beatles would’ve done, but it captured their philosophy.

Otherwise, the show was spine-tingling with its attention to detail.

It began with “Ed Sullivan” played by Jerome Patrick Hoban — who also portrayed the famed TV host in “Pulp Fiction” — starting the “shoooow” with spot-on accent and introducing old Sullivan staples Ella Fitzgerald and Sophie Tucker, only to frown when neither emerged.

He then introduced the Fab Four as “the Beatles.” The band members, looking authentic from their faces and moptops to their collarless jackets and pointed boots, began with four songs from their first Sullivan show, “I Want to Hold Your Hand,” “Please Please Me,” “All My Loving” and “From Me to You.”

They even used the “Who’s the little old man?” line from the train-car scene in the Beatles’ first movie, “A Hard Day’s Night” — to introduce Hoban’s Sullivan, who remained in the wings — and performed the title track.

The 26-song show featured only one of Harrison’s Beatles songs, “Here Comes the Sun,” which might be explained by the fact he wrote only a fraction of their entire catalog. But the Fab Four made up for that by having Pring come out to the edge of the stage to play his solos, and smile and ham it up more than the low-key Harrison ever did. It was effective, if the audience’s positive reactions are a gauge.

The Fab Four took several liberties to keep the more-casual, and perhaps younger, fans entertained, by urging them to make noise between songs — with Ardy “Paul McCartney” Sarraf rewarding one fan in the loudest section by throwing him a T-shirt.

Rolo “Ringo Starr” Sandoval also got an opportunity to shine. He showed the audience his 8-track tape of “A Hard Day’s Night,” early in the show and sang two songs with Starr vocals, “Yellow Submarine” and “With a Little Help From my Friends.” Starr was certainly more popular then Harrison during the Beatles’ 10 years together, as the Fab Four made clear.

Hoban’s Sullivan character was the perfect glue to hold the show together, part stand-up comedian, part nostalgia. After a 20-minute intermission, he came out and delivered Sullivan’s famous line about how Elvis Presley and his manager Colonel Tom Parker, whom he jokingly called “Colonel Sanders” at first, sent their best wishes to the group. He also joked that the Rolling Stones stopped by with “a reeeally big tray of brownies and I tasted them and they were delicious,” then purposely stumbled over the next few lines.

After his 10-minute monologue, a vintage film clip of British people on the street singing lines of Beatles songs left the audience in stitches, as had an earlier clip of a devout young female fan with a thick Brooklyn accent describing her painting of, and love for, McCartney.

Though the Beatles had lost the desire to perform live long before their classic 1967 album, “Sgt. Pepper’s Lonely Hearts Club Band,” the Fab Four’s interpretations of the album’s title track and its reprise, along with “With a Little Help From my Friends” and “When I’m Sixty-Four” were some of the most intriguing performances of the night. As McNeil pointed out, no sounds the audience heard were pre-recorded, and that was most remarkable during “A Day in the Life” and the single from the same period, “Strawberry Fields Forever.”

Afterward, out of makeup and relaxing with friends backstage, McNeil was told that the performance seemed more like a play than a concert. He said thank-you, as if it was the best compliment he could have gotten.