The Ironic star has been told she has cognitive phenomenon synesthesia, which causes her to experience multiple senses upon stimulation, and while she is unsure if the diagnosis is accurate, she admits she does associate colour with her everyday experiences.

"Some people describe to me the idea that I have synesthesia," she explains, 'but whether I do or not, I have no idea, but it's where you mix sensual aspects.

"People think in terms of smell or think in terms of colour. So when I meet people or I write songs or when I hear music, I can close my eyes or sometimes keep my eyes open and I see colours.

"Sometimes (when I'm writing music), if it's too harmonically primary chords, I consider the primary colours," she adds. "So I'll say, 'It's a little too yellow or red'.

"When I meet people, I am struck by... it's not aura; I can't read auras - it's too sophisticated, but I'm struck by a colour that hits me."