Lulu says she was "afraid of sex" while coming of age at the height of 1960s fame and has for the first time opened up about years of secret drinking and rehab in an exclusive extract from her forthcoming memoir, If Only You Knew, due Sept. 25.

The 76-year-old singer, who shot to stardom in 1964 with the hit "Shout" at about 15, wrote that sex felt "very self-conscious" and that conversations about intimacy had been largely absent and framed as shameful in her family. In the extract she attributes those feelings to a childhood in which sex was not discussed openly and to witnessing violence between her parents.

"I wasn’t a fan. I was a musician. But, the truth is, I was also afraid of sex," Lulu wrote, saying she preferred to cultivate romantic fantasies rather than act on them. She said she had boyfriends but that relationships rarely went beyond a "goodnight kiss," explaining that missed schooling left her with little understanding of human biology and that the candid teenage conversations seen in films were absent from her life.

Lulu described measures she took to protect herself, including staying close to her first manager, Marian, and befriending musicians' wives and girlfriends to signal she was not interested. She recalled a persistent crush on Eric Clapton, recounting that she once threw a party and invited peers ranging from the Beatles to Cat Stevens in hopes he would attend, and that she later found herself outside with him smoking and trying to appear composed.

Alongside the memoir extract, Lulu has publicly acknowledged for the first time that she is in recovery from alcoholism. In an interview with The Times, she said she had been a "secret drinker," striving to be the "best Lulu" while fearing she might become like her father. She said her drinking was once controllable but worsened in her sixties after menopause, the deaths of her parents and the departure of her son from home.

"For many years, and I can’t say how many, I had not been happy with the way I felt, not at all happy and [yet] unable to ask for help," she said, adding that reading memoirs and self-help books informed her decision to speak about her experience. Lulu said she has sought help in rehab and described recovery as part of addressing what she called a family illness.

Her memoir also details traumatic scenes from her upbringing, including violent domestic incidents and an episode when her father was "dragged away" by police. She said she had long carried "shame" about her parents' behaviour but now describes them as "damaged." Lulu linked her alcoholism to years of suppressing feelings while maintaining a professional image and supporting her family.

Lulu, who has been married twice — to Maurice Gibb from 1969 to 1973 and to hairdresser John Frieda from 1977 to 1991 — said she is now living in a "brighter" world in central London with her cockapoo. If Only You Knew is published by Hodder & Stoughton and is scheduled for release on Sept. 25. The singer is due to begin a tour at the end of September.