IT’s probably the most loved and revered album ever made and is still a bestseller, 50 years on. So it’s a brave man who meddles with Sergeant Pepper’s Lonely Hearts Club Band...

And as American composer Ethan Iverson admits: “There’s nothing potentially more terrible than a Beatles’ covers project.”

Thankfully, he’s pulled it off with an innovative score that is far from terrible. Ethan provides the music for Pepperland, a new production from the acclaimed Mark Morris Dance Group, which includes six reinventions of song on the album, including Penny Lane and With A Little Help From My Friends, performed by a seven-piece band, led by Ethan on piano.

Described by the New York Times as the “most successful and influential choreographer alive”, Mark Morris founded his company in 1980 and many of its 150 works are considered masterpieces.

The New York-based contemporary company was asked to create the piece by the City of Liverpool to mark the 50th anniversary of Sgt Pepper. Hailed as the first-ever ‘art rock’ album and widely regarded as the best album of all time, the Beatles classic spent 27 weeks at the top of the UK chart and 15 weeks in America. It won four Grammy Awards in 1968.

“When Mark Morris called me I realised what a daunting project we were taking on,” says Ethan, 45. “It could be awful, but Mark’s such a genius I thought I could do it with him. The album is a favourite record of mine from high school. They made a masterpiece, really, and each new generation discovers it with awe. It’s important to note that Pepperland isn’t like a Beatles’ concert and people shouldn’t expect that. Their music is the fundamental backbone of the piece. We take liberties with it like we would with Twinkle Twinkle Little Star, pieces we know so well but can change.

“The score is played by remarkable jazz musicians, the best in the world. They need to be as it’s an incredibly complicated album. Your average bar band couldn’t play covers from it. It’s almost symphonic in scope.”

Adds Ethan: “Part of the commission was for an electronic element. They probably wanted a DJ or hip hop sampling, but trying to do the latest thing felt forced. So I went for the first electronic instrument, that’s nearly 100-years-old. Invented by Leon Theremin in the 1920s, it’s incredibly difficult to play it well and requires a particular type of genius.

“I had listened to this wonderful theremin player, Rob Schwimmer, playing Bach’s Air on a G String. It was one of the most beautiful things I’d ever heard and made me cry. I really wanted to work with him and Pepperland was the perfect opportunity. When Rob starts to play A Day In The Life on the theremin, it stops the show. It’s a heck of a moment.”

Sgt Pepper has a range of musical styles, from psychedelic and Indian to music hall, and Pepperland nods to them all.

“The first thing we hear on the album is a guitar blues lick, which I expanded into a blues piece for horns,” says Ethan.

“I know Mark so well that while I was composing I kept thinking of dance moves he could put to it. It was like giving him a softball and saying: ‘Go on, knock this one out of the park!’ Of course, the choreography didn’t really turn out like that.”

As a self-confessed anglophile, Ethan is looking forward to the UK tour. “I grew up watching the BBC and as a child I was obsessed with Doctor Who. I’ve been to England a lot and love your music. I wouldn’t say the Beatles were the best British band ever, but I do think the best rock has been made by British bands.

“It’s a thrill-and-a-half to be part of Pepperland. It’s a fun show. There’s a certain amount of darkness, but it’s a very joyful piece.

“Pepperland has no political commentary whatsoever. It’s joy for joy’s sake, an escape which takes you to another place.”

n Pepperland is at the Alhambra on Tuesday, April 2 and Wednesday, April 3. Call (01274) 432000.