That much-loved popular literary saga of forbidden passion and Catholic guilt set in the wild open spaces of the Outback, The Thorn Birds, is to be staged as a musical, 30 years after it caused a publishing sensation.

The book's reclusive Australian author, Colleen McCullough, has jealously guarded her work from all other attempts to adapt it for the stage, but this weekend the 71-year-old writer has announced plans to premiere a new musical version, directed by the award-winning Michael Bogdanov, before it starts a tour of Britain this spring.

McCullough's novel, which has sold more than 30m copies since it was published in 1977, is still regarded by many fans as the most romantic ever written. Germaine Greer recently dubbed it 'the best bad book ever' in response to publisher Virago's decision to reissue it as a modern classic.

The American mini-series based on the book, broadcast in Britain in the early 1980s, remains one of the most widely viewed television dramas. Starring Richard Chamberlain as an errant Catholic priest and Rachel Ward as his young lover, it was beaten into second place for audience numbers only by Roots, the groundbreaking American series about race.

"There are certain iconic moments in television history that mean something to people and The Thorn Birds was one of these," said Bogdanov.

McCullough wrote the first draft of her hit novel in just three months in the evenings after her day job as an impoverished neurophysicist working in the laboratories at Yale University in America. The publication of The Thorn Birds promptly turned her life upside down. Its huge international success forced her to give up academia and in the late 70s she moved to a remote Pacific island to avoid the pressures of fame. Concentrating on other kinds of writing, including a seven-volume series on the history of Rome, McCullough did not pick up a copy of The Thorn Birds for 25 years until Gloria Bruni, a German composer and opera star, sent her some of the songs she had written, inspired by the story. The two women have since collaborated on the content of the show, but were not happy with "the book" of their new musical until Bogdanov became involved.

"I picked up a copy of the book at Cardiff airport on my way to America shortly after Colleen and Gloria contacted me," said Bogdanov this weekend. "I had not read it before, but I found, like most people, I could not put it down. As soon as I landed in America I contacted them and said I wanted to work on the musical with them."

Bogdanov, who has directed opera and musicals and who set up the acclaimed English Shakespeare Company after a period in the 1980s working at the National Theatre as Sir Peter Hall's associate director, travelled to McCullough's home on the remote Norfolk Island, a former penal colony 1,000 miles off the Brisbane coast, to work on the dialogue.

He and Bruni also worked with McCullough on the script in Wales, where Bodganov now runs the Wales Theatre Company, the company behind the new musical.

The role of Meggie Cleary has gone to West End musical talent Helen Anker and the role of dashing priest Ralph de Bricassart has yet to be cast. "It is going to be a challenge to suggest that sense of loneliness on the stage," said Bogdanov, "but I can see how we can do it. Expectations are going to be very high, but I have been determined to get the right narrative structure."

The costumes for the show's cast of 18 have been designed by David Emmanuel, the man behind Diana, Princess of Wales's wedding dress.