Mamma Mia! is one of the most successful musicals of all time, inspiring the famous film and entertaining millions worldwide, such is its notoriety.

Taking Abba's biggest hits and sculpting them around the now beloved story of a couple getting married on a Greek island where the bride's eccentric mother lives, was an immediate hit, the concept spreading like lit torch paper when it opened in the West End in 1999, and the story has been playing out on stages around the world ever since.

And now, the cult musical is on tour and coming to Oxford for two weeks, to spread the same magic and joy enjoyed on the world's biggest stages.

Leading the vast cast as the matriach Donna (immortalised for ever on screen by Meryl Streep) is Helen Hobson, belting out the shows biggest numbers, such as such hits as Super Trouper, Lay All Your Love on Me, Dancing Queen, Knowing Me, Knowing You, Take a Chance on Me, Thank You for the Music, Money, Money, Money, The Winner Takes It All, Voulez-Vous, SOS and the title track, night after night.

A tall order perhaps, but for someone who had been secretly cherishing the role, desperate for her turn to play the iconic figure, it's still a dream come true.

"I did the international tour which was seen by the West End producers so when the part came up in London I didn't even have to audition," she remembers.

And despite having a seven month old baby at the time, she transformed into Donna every night.

The Sound Of Music followed, and then Mamma Mia's bosses rang to ask whether Helen was interested in taking the musical on tour.

"I said no, of course not. I have a six year-old child and a family. I can't just drop everything and go travelling around the country.

"But they kept ringing and slowly I thawed, because they know how much I love playing Donna. So now I'm back on 'the island' as we call it, because it is such an extraordinary show."

What is it that she loves so much about it? "It's such a unique beast because each new recreation is improvised to encompass the actors in it, even though it's the same set and script, which means it's always fresh.

"Maybe that's why the audience loves it so much, because the cast enjoy every single minute of the performance. It's such an honour to be in.

"But then that's the power of Abba's music. It gives the show so much energy. It reaches out to you and to the audiences and they already know the words."

Which is all well and good, but ABBA were also brilliant performers which is why Helen gets picked time and time again.

So how does she stay match fit? "I am really strict with myself on tour and have a fierce regime of healthy food, lots of water, sleep and exercise. Because I have to wear a lot of jumpsuits, lycra and Swarovski crystals, so the exercise is fairly crucial," she laughs.

"Other than that I just try to be in the moment and to give it 100%. It's mind over matter."

With musicals such as Blood Brothers, Les Miserables, Heathcliffe, Passion, Jesus Christ Superstar, Miss Saigon and My Fair Lady under her belt, Helen is nothing if not a pro.

So how does she manage to juggle her professional and private life? "I have amazing family support and a stay-at-home husband. He's in the same business, so we take it in turns to work. But the tour ends in March and then I'll be home. It's different for everyone I suppose."

Mamma Mia! Tuesday 14 - Saturday 25 November. New Theatre 0844 8713020 or atgtickets.com