"But it also became the best way, to just have the music in its purest form," she says. "Don't like my music because you think I'm attractive, or because of what I'm wearing, or because of who I'm associated with. Be about my message, and that's it."

The message has evolved over three collections of raw, downbeat R&B, from the distanced yearning of 2016's Volume 1 to something more sexually assertive on last year's Volume 2. Despite the growing interest, the forced mystique has remained.

"A lot of people they're signed because they have a lot of followers, or because they look a certain way, and I just don't believe that's what's important when it comes to music," she says.

Of course, listeners love a mystery. After her debut EP earned shout-outs from the likes of Alicia Keys and Rihanna, online sleuths tracked H.E.R. to Gabi Wilson, a young singer who’d achieved some viral success as a pre-teen with appearances on Good Morning America and The View.

In person, she's open with details of those earlier years – how a Filipina mother ("Filipinos love karaoke") and a father who jammed with funk and soul bands ("There were always instruments in our living room") fuelled her vocation; how her manager Jeff Robinson "leveraged" his previous success in launching the career of Alicia Keys to convince record label RCA to embrace H.E.R.'s anonymity, when even Sia needed a few ARIAs under her belt before she could hide her face away – but at this stage "Gabi Wilson" remains off limits.

"A lot of people say, 'Why is she hiding?' I'm not hiding. If anything, you know more about me than you would if you only saw my face and knew my name," says H.E.R. about her emotionally honest music.

"The music is the important part, and the message is the important part. That's the part that shows who I really am."

H.E.R. performs at the Sydney Opera House, as part of Vivid, on Tuesday night.