‘Baby, It’s Cold Outside’ was a Christmas classic for more than half a century until people suddenly began to worry that it was about yuletide date rape. ‘It was because of the video Tom Jones and I made,’ says Cerys Matthews, in her smoky Welsh lilt. She recorded a cover with Jones in 1999. The video showed the craggy old Welsh crooner slip something in her drink that turns Cerys into a high camp vamp. ‘The song is really innocent and beautiful and fun — it’s got a huge heap of humour and wit and I love it. That song is not our enemy. That woman is a strong woman. She’s there because she wants to be! It’s cold outside. They’re making love. Come on!’

Cerys herself was exposed to explicitrecord content when she was a child. ‘Famine, religious persecution, genocide, injustice, political manoeuvrings.’ She makes a list. ‘I had a book of Irish ballads when I was about nine and it’s full of war songs where they’re maimed and they’re injured and they’re insane and they’re eyeless and legless and armless and they’re putting out a bowl to beg. All these songs — they’re full of life and there are no taboo subjects. This was a way of spreading news, a way of processing things, a way of trying to teach people and enlighten people. They’re wonderful songs.’

If you are, like me (and her other 700,000 listeners), addicted to Cerys’s BBC radio show, you may think she gets away with quite a lot already — no song is too esoteric, no sound too peculiar: ‘I’ve invited buskers on the show before, dulcimer players, zither players, glass harmonium players from Ukraine that I met in Venice… strange sounds like mating haddocks, whales speaking like men, elephants speaking like men, squeaking frogs.’ Finally, she reckons, she’s found the place she’s meant to be.

Born in Cardiff in 1969, Cerys ‘rhymes with terrace’ Matthews is the second of four children and she spent her early years on a farm. The idea behind the festival she’s created — the Good Life Experience, which takes place next month — is to recreate the conditions of her running-wild childhood in Wales, to let kids ‘off the leash’ so they ‘gain a sense of independence and responsibility and enlightenment — to get the chance to forage or see how a knife is forged, or sharpen an axe or make your own pizza dough and put it on the fire. All those kinds of things that quite often in modern life we simply can’t really do.’

She was an oddball from a very early age — when her older sister knocked all her own teeth out playing on an iron horse, Cerys coveted her dentures. She first discovered she had a voice aged nine when she was singing ‘All My Trials’ — a track in which Joan Baez contemplates suicide — to herself in a tent in her back garden, only to find she had an unseen audience of relatives who all started clapping.

At an age when other girls were forming their first crushes, Cerys became obsessed with Bob Dylan. But not in a poster-on-the-wall sense — she wanted to be him. ‘I was very keen on sounding like Bob Dylan and I have a very high voice,’ she recalls. ‘So I started drinking whisky and smoking when I was very young — deliberately to have a more Bob Dylan-like voice. That’s just the logic of a child…’ Or, possibly, just the logic of Cerys, which is a logic unto itself.

Right now, she doesn’t want to talk about what made her famous — fronting the Britpop band Catatonia. ‘I don’t care about more fleeting things,’ she explains, ‘I don’t really care about fame and smoke and mirrors of celebrity.’

Legend has it the band was formed in 1990, when Mark Roberts, Cerys’s soon-to-be boyfriend and song-writing partner, spotted her busking outside Debenhams in Cardiff. For the next eight years they gigged away without much success and then wrote a break-up album, ‘International Velvet’, which became a massive hit. The songs ‘Road Rage’ and ‘Mulder and Scully’ — which are essentially about couples who hate each other — were the soundtrack of 1998. If you remember them fondly, do not hum them in your head. They’ll get stuck there.

Cerys became ‘Cerys’ (losing the surname in the ‘I’m so famous’ sort of a way), as renowned for her antics as her lyrics. She was given to insulting people in Welsh, such as the weather forecaster Siân Lloyd. She gave good quotes (‘if I sang with any more of an accent, the Welsh tourist board would sponsor me and set me in concrete’). She disappeared after a gig in Southampton and came to in the south of France with no idea how she got there. Wore a T-shirt that branded her a ‘fast-rising lager-soaked rip-roaring pop tart’. Threw a TV out of a window (her own)… cue textbook rock-star meltdown.

‘I couldn’t walk, couldn’t breathe,’ she told the Scotsman in 2006, recalling spiralling out of control and quitting the band. ‘I was allergic to heroin. My body would react against it. It fills your lungs up.’ Luckily, Bob Dylan called — she’s never talked about what her hero said, but it obviously meant a lot to her. ‘It gave me the courage and the confidence and the energy to change the pages and move into a new chapter,’ she says.

She absconded to a shack in Nashville, fell in love with her first husband (turning up to the ceremony in a tractor, which according to the Independent makes her ‘the only celebrity to have had her wedding photos splashed in Hello! and Farming Equipment News’) and had the first two of her three children (Glenys Pearl Y Felin, now 16, and Johnny Tupelo Jones, 14).

The reason Cerys doesn’t want to talk about Catatonia is because she’s fresh from seeing a tribute to Nina Simone at the Proms. ‘I mean she was extraordinary,’ she insists. ‘So I don’t think about me as a songwriter… selling a few records, when there’s people like Nina…’ I can see her point. If I was comparing myself with Joan Didion right now, I should just stop writing entirely.

But while Cerys doesn’t want to recall it, if you’re middle-aged then Catatonia was the soundtrack to your youth. So in that context the most controversial thing she’s done was probably coming fourth on I’m A Celebrity… Get Me Out Of Here! shortly after getting divorced in 2007. ‘The news that she was taking part was accompanied by gasps of pity and mild despair from almost everyone I know,’ Charlie Brooker wrote at the time. ‘“Why?” they all said. “Why? It’s such a shame.” It’s a bit like when Kirsty MacColl died.’

While in the jungle, she became romantically involved with an actor you’ve never heard of and post-fact posed for saucy snaps in the News of the World. ‘After an initial reaction of “Why don’t I have an ass like that?” I was shocked,’ moaned one music critic. ‘Though not a fan of her music… I feel betrayed.’

Now very happily married to her manager, Steve Abbott (with whom she also has a nine-year-old son, Red), Cerys has clawed her way back into highbrow hearts with her BBC Radio 6 Music show where she plays whatever she damn well pleases and interviews anyone she damn well pleases too. Her favourites include astronaut Helen Sharman (who told her the greenest parts of the Earth from space were Ireland and New Zealand) and the grandson of ‘Sir Joseph Bazalgette — who had the foresight to build massive sewers so the likes of us so many generations later can still poo in peace — so we had a great playlist of Velvet Underground, something else to do with underground, and pipes and… you get the drift’.

For Cerys, making such connections is what life is about, so her cookbook, Where The Wild Cooks Go, is a distillation not only of recipes but ‘poems, music, curiosities, history, characters, quotes, proverbs’, and she’s going to go on defending and playing the records she loves until she ceases to exist. ‘We are here on this earth for a blink of an eye and yet we’ve got all these strands that lead us back to our ancestors and are leading into the future,’ she explains. ‘Like Bob Dylan, he’s not going to go away when he dies. He’s going to be like Confucius. And the more we can try and make sense of these strands, and question who these people are and why they are so extraordinary, then the more sense we can make of our own time on the land. That’s all I really care about.’