Long before Louis Theroux went on his first Weird Weekend, Ruby Wax was chipping away at the shiny coalface of celebrity culture and documenting offbeat US tribes to the delight of the viewing public.

Now the comedian, actress, writer and mental health campaigner says she "can't get a job on television" and was forced to "reinvent" when her TV career took a nosedive after she turned 50.

Wax, who is about to embark on her first tour in four years, told Sky News: "I'm grateful I got to do those shows. It's a job everybody wants. But after 25 years, you think, What else?"

She goes on: "It's over when it's over. It was over early for me".

Open about her mental health battles over the years, and an ambassador for mental health charities MIND and SANE, Wax admits that the pursuit of fame was an addiction of sorts: "I was so interested in fame… Studying what's the effect of fame on people. Because it's fabulous to get in a restaurant using your own name, but it's also a curse because when they take it from you, it's like coming off a drug."

Throughout the 90s and early 2000s Wax grilled A-listers, future world leaders and public figures - holding a mirror up to celebrity culture of the decade.

She captured the zeitgeist with her fearless celebrity interviews, chatting to stars including Pamela Anderson, Madonna, Tom Hanks and the Spice Girls.

And she didn't just do softball interviews.

More tricky interviewees included Donald Trump (he called Wax obnoxious and kicked her off his private plane, she went on to label it the worst interview she'd ever done); OJ Simpson (Wax had hoped he would confess to the murder of his ex-wife Nicole Brown Simpson on the show; He didn't, but later called her on April Fool's day to tell her "I did it" before adding, "April Fool"); Bill Cosby (he play-acted taking a phone call during their interview, comparing chatting with Wax to "talking to an answering machine you can't fix", while she later branded his behaviour "psychotic") and former first lady of the Philippines Imelda Marcos too.

Shining a spotlight on the now much talked about topics of celebrity culture and fame, Wax was the first women to front gonzo style documentary interviews and make them a hit in a primetime slot to boot.

Wax on Trump: 'I hated speaking to him. I found him toxic'

She also did a series looking at American subculture - Ruby's American Pie - in the late 90s, investigating themes including the Klu Klux Klan (KKK), offbeat religion and porn. Again, all themes in Louis Theroux's wheelhouse, at around the same time.

But unlike with Theroux, there was no faux-naif front with Wax, she went in full throttle with her brash American approach - which sometimes worked a treat, and other times less so.

On her infamous interview with future president Donald Trump (who was then just a billionaire real estate magnate and presidential hopeful) Wax told Sky News: "I hated speaking to him. I found him toxic.

"I didn't think I was going to learn anything. I just thought this is a terrible experience, just horrible. And so was Bill Cosby. I didn't think, 'I'm going to show the world something'. I just found him repellent, and he frightened me because he is so toxic, and he hated me. So that doesn't help an interview."

Trump went on to throw her off his private plane - complete with a gold sink and cushioned bidet. Wax says: "I think I could have handled it better. You don't see the fear in my eyes, but it doesn't feel good."

'I had to re-invent. I can't get a job on television'

Despite her own harsh review of some of her interviews, the audience lapped up her no-nonsense approach, and her shows were a hit.

A stalwart of BBC output through the nineties - The Full Wax was followed by Ruby Wax meets…and after a gap of a year or two The Ruby Wax Show followed suit in the early 2000s.

But while Theroux's shows are on constant re-run, and he's given this year's prestigious MacTaggart lecture to industry big wigs at the Edinburgh Television Festival, Wax is largely a stranger to today's TV schedule.

Her rivalry with the fellow celebrity documentary maker has been well documented, with the pair finally forging a truce of sorts after he interviewed her at end of 2020 as part of his Grounded COVID podcast series.

As for his flourishing career, she says: "I sort of see why Louis carried on, because he played himself and I was playing kind of a character… I turned 50, and that's against the law. You can only play people who have a terminal disease or are dead when you're that age. So, I had to re-invent. I can't get a job on television."

'I'm not like Graham Norton'

However, she admits the modern-day celebrity interview is less attractive than in days gone by.

"I wouldn't really like to do any more interview shows because you can't get celebrities the way I could. Now, there's too much PR and they're too careful.

"In my day, I could interview them for a week, and that was pleasurable. I'm not like Graham Norton, where you can chew 'em out in 15 minutes. I wouldn't be good at that."

But Wax says she would have liked a shot at more cerebral shows too, adding: "I would have liked to do Newsnight. I'm really smart."

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A woman of many talents, Wax is also a classically trained actor (she spent five years with the Royal Shakespeare Company) and was awarded an OBE for her services to mental health in 2015.

Now with a tour about to start - documenting a search for the meaning of life which ended up in a psychiatric ward - a reinvented Wax admits: "I'm always running."

Unlike many performers who dread a tour, Wax says: "I like living out of a suitcase and I like meeting new people. I think it's because my parents were refugees and they knew how to decamp within three minutes. And so, I have that in my DNA. I love it.

Wax's tour - I'm Not As Well As I Thought I Was - kicks off on 14 September in Brighton, and runs until late November. The book is out now.