Corkman John Duignan saw secret Scientology files on celebrities, including Van Morrison and George Harrison, when he was part of the cult's elite group, Seaorg.
Duignan rose to a position of Commanding Officer in Seaorg, a special unit that dresses in naval uniform.
He told the Irish Independent that the church had unsuccessfully tried to recruit Van Morrison and he had shown an interest. The sleeve of his 1983 album, Inarticulate Speech of the Heart, has a tribute to the founder, L Ron Hubbard.
Duignan said: "They kept files on everyone, particularly those who were famous. I was involved in putting them on computer in London.
"They were trying to involve Van Morrison, but the problem was that that the auditor who was supposed to be looking after him was starstruck, and seemed only interested in talking to him about his career.''
Later on they approached Van again, but he did not join, according to John Duignan.
He said the 1960s file for George Harrison showed that the Beatle had bought one Scientology book, but did not persist with the cult.
Although he rose to a senior position, John said he worked long hours for minuscule wages. For much of his time in Seaorg, he said he lived in dormitories on a diet of beans and rice.
Duignan broke away in 2006 after he became disillusioned with the gulf between the opulent lifestyle of the church's senior figures and its rank-and-file workers.
