Having been nominated for a Grammy award for her self-titled debut album in 1967, she was befriended by some of the most iconic rock stars of the '60s, including Jimi Hendrix and Janis Joplin. "Nobody knew who was going to be a legend… they were just people who were very good to me when I was young," she says. "They didn't let my age interfere and they taught me what they could. I don't know how to explain what Janis and Jimi were like, but I certainly didn't look at them as icons, because they were my friends and because they weren't iconic back then.
"I remember doing cocaine with Hendrix, but it was a mistake, because I actually turned out to be allergic to cocaine," she giggles. "I was really fortunate, because I think I coke would have been the perfect drug for me - more speed and more energy.
"I have so many memories. I probably played with Hendrix 15 or 20 times during the time that I knew him, and I would absolutely love to hear that stuff, because I certainly never heard it back then."
Having become a star at such a young age, did she feel as if she had missed out by not having a more conventional life as a teenager? "It was good to start young and to learn that what matters is the music. I only know the life I lived, and I got most of my mistakes over with before I was 21. Instead of working in a day-job that I hated, I got to deal with everything from death threats to doing coke with Jimi Hendrix. I lived an entire life in my teen years, and I don't regret a second of it."
Within a few years, Ian had released a handful of mature albums, attempted suicide and retired from music altogether: "Yeah, I tried to kill myself when I was 18," she says casually, "but honestly, I'm not sure how much of that was adolescence, how much was just how I was born and how much was actually the pressure I was under. Somebody overdosed me with acid when I was 16, and I think I started fragmenting after that. Life in the spotlight doesn't leave you a lot of time to be creative, so I watched my songwriting go downhill and I decided to retire.
"This may sound pretentious, but I had already played Carnegie Hall by the time I was 17, so I'd pretty much done what I'd originally set out to do. I remember walking off the stage at the Philharmonic Hall and telling my manager I was stopping, and she laughed and said: 'Well, they all say that.' I said: 'Well, I'm actually doing it.' I moved out of New York, got some good therapy and I put myself back together and became a songwriter."
After a three-year interval, Ian returned to the spotlight in 1973. Over the next few years, she released a clutch of albums and became a household name thanks to a handful of songs such as Stars, Jesse and At Seventeen – a moving and memorable appraisal of teenage loneliness. "At Seventeen is painfully honest, and I sang it with my eyes closed for the first six months because I was so sure everybody would be laughing at me," Ian sighs.
"The willingness to be open is a lot of what creates the pathos in that song. The one and only thing that I do better than most of my contemporaries is talk about things that are hard for people to say, and that's what people love about a song like At Seventeen."
Ian walked away from her recording contract with CBS in 1981 before disappearing once again: "I could have stayed there like Billy Joel and Leonard Cohen did, but they had lost interest in my music by that point," she says.
"It was probably just as well that I left, because being signed to a major label right now is something that's for kids. I think I would have been old news there, no matter what I did. You can be Bruce Springsteen and be in your sixties and nobody thinks anything of it, but if you're a female pop singer in your sixties, it's just not acceptable. It's different for a girl."
She eventually got married and divorced, lost her home and her life savings to an unscrupulous business manager and moved out to Nashville, "penniless and hungry to write". She re-emerged in 1992 and received her ninth Grammy nomination for her comeback album - the aptly-titled Breaking Silence - which amongst other themes, chronicled her recent coming out as a lesbian.
Looking back on her career, how important is the concept of her own musical legacy? "I care that my music touches people, but what do I care what happens once I'm dead? I can't believe that Beethoven sat around worrying about posterity, and I'm certainly not gonna be remembered like Beethoven," she laughs.
