A Former member of Britain's Got Talent stars Jive Aces claims the band tried to "brainwash" him into becoming a Scientologist.
Guitarist Johnny Gunner says the other members tried to control his behaviour after they joined the religion — and he felt relieved to leave the band.
Johnny, 47, said his old pals were introduced to Scientology — set up by L Ron Hubbard in 1953 — by a man handing out leaflets in London.
Soon after, Johnny of Southend, Essex, was asked to move in with the band. He said: "They were being brainwashed.
"I thought I was in danger. I was in the band to play music not be part of a secret religion. It got to the stage where they said join us or leave. They were a strange bunch."
He quit months later, saying he couldn't commit to the band.
Jive Aces impressed judges on Saturday, performing the Jungle Book theme. Singer Ian Clarkson said: "Scientology has helped me and the band creatively. If anyone asks, I suggest people read L Ron Hubbard. There's no brainwashing."
A band spokeswoman said: "Johnny Gunner left in 1989. The band did not become Scientologists until 1991."