'That's really funny, if you think about it," Ruby Wax says, grappling to catch her breath through wheezing laughter, her gravelly voice ascending a couple of semi-tones.
"I never thought for one second that my own sickness would be a means to showbusiness," she says, engulfed in giggles.
"I mean, c'mon, who knew? I certainly didn't."
It's more of a career rebirth, really. Wax (60) has recently become the poster woman for mental illness, a mantle she wears proudly. Seven years ago, she experienced, as she calls it, "the tsunami of all depressions", and woke to find herself institutionalised in the Priory, unable to leave her chair for five months and staring catatonically into space.
The brash American TV personality had always suffered from depression, with bouts alternating every five years. It would generally last a couple of days, but steadily became worse as she got older.
"When I was young, we thought this was some kind of virus," she explains. "Nobody dealt with it. They just assumed I would get over it. Nobody knew anything at the time. I can't even remember the first time it happened. I probably just thought it was the flu.
"In college, I would go to bed for a few days and sleep, although it was more an awake sleep. The bouts started to get longer and the last time, the worst time, it was months – months of this semi-conscious state."
Inspired by her experience, she penned a one-woman show, 'Live From The Priory', with friend Judith Owens and played it to private and public mental-health institutions around the UK.
"It felt like we were giving the illness a platform, and those suffering from it – in silence for so long – a voice to talk about it. It gave me a voice to talk about it.
"There's nothing that a person with depression likes more than another person with depression," she laughs. "It's like sucking your thumb."
Many celebrities over the years have quietly alluded to their struggle with mental illness, from George Michael and Kylie Minogue to Jack Dee and Carrie Fisher.
Ex-boxer Frank Bruno and former comedy queen Caroline Aherne famously endured severe bouts and quietly slipped out of the spotlight soon afterwards.
Sufferers saw their illness swept under the rug by a media unable to define it, yet other physical illnesses, such as cancer and HIV, never left the headlines.
Two years after the placement in the Priory, Wax inadvertently became the face of mental illness after allowing her face to be plastered all over the London Underground for Comic Relief with a simple caption: 'I suffer from depression.'
Wax is a showbiz enigma: a woman who has crossed the line between stand-up and red carpet; stage and celluloid and has moved back and forth between fiction and reality TV.
With her wild hair, bold red lips and unmistakable drawl, she played to the American stereotype and became a regular fixture on our screens.
She was at the height of her popularity in the mid-1990s with her BBC series 'Ruby Wax Meets...' She leapt into bed with Madonna to discuss preferred sexual positions and later squeezed into a red swimsuit to run alongside the surf with Pamela Anderson.