A few years ago, I lay in my garden on a hot summer’s day, listening to a few familiar notes of a song wafting over from next door. As it reached the chorus, I mimed along. When my neighbour played it for a third time, I was tempted to shout: “You OK?” I knew they weren’t: anyone listening constantly to kd lang’s Constant Craving, a paean to longing and desire, was surely in the throes of a deep and unrequited crush.

The track, released in 1992, is the last on lang’s second album, Ingénue. The Grammy award-nominated, multi-platinum-selling album became a cultural milestone – it hoisted LGBT issues firmly into the mainstream, and subverted country music, which was then the preserve of a far smaller, more conservative audience. Ingénue is meditative and personal, its vulnerability and honesty resonating strongly.

Now 57, lang is about to embark on a UK tour called Ingénue Redux, where she will play the album in its entirety. “The first time I listened back, after 25 years, was when we were rehearsing,” she says, speaking from her home in Calgary. “I thought: ‘Ugh, this is not going to be easy. It’s a dirge, it’s so slow.’” But when she had completely relearned the album: “It felt like putting on an old pair of shoes.”

Each note of the record is as clean and brilliant as polished marble; each instrument is given room to breathe; the lyrics are clear, so there is no misunderstanding of her message. “We were sticklers for the sonic cleanliness of that album,” she says. While her first album, 1988’s Shadowland, had a much stronger country flavour, Ingénue adds a cabaret influence. But its momentous success nearly was not to be.

In 1992, Kathryn Dawn Lang came out as gay during an interview with the Advocate, an LGBT magazine, while promoting the album. Some radio stations stopped playing her music; she felt ostracised by the country music industry. In 1993, she appeared on the cover of Vanity Fair. She had continuously played up to, and cultivated, her androgynous looks – rocking a teddy-boy quiff and often a loosely tailored suit on stage. For the magazine shoot, she appears in a barber’s chair, her tie loosened around her neck, with her face being shaved by Cindy Crawford. The image is disruptive, beautiful and poignant: it’s no longer a man’s world. “Elvis lives, and she’s beautiful,” Madonna said at the time.

“I was surprised when I heard a rumour that I’d slept with Madonna,” lang chuckles. “I was completely oblivious to it.” How did she feel about being the centre of so much attention? “It’s a byproduct of showbusiness. And really, that’s one of the reasons I don’t like participating in showbusiness.”

She says she spends a lot of time with her mother and partner. She cooks – “I’m a great home chef” – and is a practising Buddhist, with her own meditation room. A keen advocate for the animal rights group Peta, she has been vegetarian since she was 19. After seven studio and six collaborative albums, the allure of the music business has dimmed. “I’m excited to tour because, to me, it’s just about singing for people. But it has not ignited a deep thrust to make more music.”

‘I was surprised when I heard a rumour that I’d slept with Madonna’ ... kd lang with Cher, Madonna, Joni Mitchell and others at the Vanity Fair post-Oscar party in 1998. Photograph: BEI/REX

It must have been hard, so much of her life being public property. “I grew up with the adage that there is a wealth of purpose in being mysterious,” she says. “And I feel like I haven’t had the chance to be mysterious. My sexuality, and everything, was so much out in the open, and has been for many years. I feel exhausted by being exposed. And it’s truly not that interesting!” She tails off with a laugh.

Although it might not seem interesting to her, at the time lang came out, she pretty much represented an entire section of society. The early 90s were a fallow time for famous lesbians – she quickly became a sapphic north star. As someone who was barely scraping into their teens when Ingénue was released, I was aware of lang, although I don’t think I had heard her music. Awareness of her existence allowed me to realise that there was another choice available apart from heterosexuality.

Does she recognise that she opened the door for others to walk through? “Um, yeah, although I try not to take huge credit for that because it’s not a competition. It’s something bigger than all of us. I am certainly proud, but at the same time, I’m just one of many. Gay culture isn’t just one sliver of humanity – it’s a huge cross-section of people.”

Pop is one of the few cultural movements where the young are ascribed more power than the old. Often, it can feel like young pop stars are given credit for things lang was doing well before they were born: playing with gender and image, blurring the lines between what it is to be masculine or feminine. There is obviously still a power in the subversion, but do they have to fight in the way that she did? A pause. “Women are still fighting, and people of colour are still fighting, and gay people are still fighting.”

There’s are so many rightwing forces at work right now providing and fuelling hatred kd lang

I mention the recent homophobic assault of two women on a London bus and how it showed that there is still a lot of work to be done. “The bottom line is that everyone wants to feel accepted, including the guys that inflicted the violence,” lang says. “They feel threatened by women who chose to be with women because society has constructed this game plan – right now, there are so many rightwing forces at work providing and fuelling hatred.”

While writing Ingénue, lang hoped it would stand the test of time, and it has. In the meantime, humanity has changed; LGBT rights have advanced enormously, although still not enough. Desire and vulnerability remain constants. Heartbreak makes you who you are. Feeling you don’t belong is universal – and there is a paradox in feeling “seen” by a poetic outsider. As my neighbour could attest, sometimes you need music, slinky songs of love and lust, to swirl around you on a summer’s day, to make you understand those feelings. As lang sings: “Constant craving, has always been.”

kd lang’s UK tour starts on 13 July