Meryl Streep hits a high note

Meryl Streep is best known for her serious roles in films like Out Of Africa, so it's really quite hard to imagine her as a flamboyant Lycra-clad blonde, belting out Super Trouper and other camp Abba numbers.

But this is exactly the surprising transformation the two-time Oscar-winner has undergone for one of this summer's brightest blockbusters - the film adaptation of the hit musical Mamma Mia!

When we meet at an elegant hotel in London, Meryl is looking her usual demure self - but she's mischievous, and keen to dispel the idea that she's out of place in musicals.

"I've done a lot of musicals in my life. My first Broadway show was a musical and then I'd done a lot of musicals in high school, so it was like coming home to a thing that I always loved doing," she says.

"I haven't done many because I haven't done much stage, even though I wanted to, in a long time... And people are afraid to make musicals into movies."

Meryl heads an impressive cast-list as Donna, a hippy mum running a guest house on a Greek island, whose only daughter Sophie (Amanda Seyfried) is about to get married.

Unknown to Donna, Sophie has pinched her mum's diary from the year she was born and has invited her three potential fathers (played by Pierce Brosnan, Colin Firth and Stellan Skarsgard) to her wedding, although her mum hasn't seen them in 20 years.

Cue much mayhem in the sweltering heat as Sophie tries to work out which man is her dad and Donna tries to chase them off the island - all set to various Abba classics.

One of the funniest, and most surreal moments comes during Sophie's hen party, when Donna and her best friends (played by Julie Walters and Christine Baranski) squeeze back into their platform boots and colourful flares to perform one more time as 1970s band Donna And The Dynamos.

Meryl, who recently turned 59 but doesn't look anywhere near it, actually fell in love with Mamma Mia! long before she was singled out as the 'ideal' actress to play Donna, after watching it on Broadway in 2001.

"I took my ten-year-old and her birthday party right after it had opened. It was right after September 11 and everyone was feeling really low and I thought, 'What am I going to do with all these kids?'," she explains.

"I saw an ad in the New York Times and it said 'new British musical' and something about 'buoyant fun' and I thought, 'Boy! I'm there'.

"I took the kids and we were all just dancing in the aisles and down the street. I bought the cast album and sang the songs for two years.

"And I wrote a note to the cast to basically say, 'Thank you for the music' and thank you for the injection of joy that was so needful at that moment."

The actress, who has four children with her husband of almost 30 years Don Gummer, admits she was apprehensive about her now grown-up offspring seeing their mum in psychedelic 1970s gear for some of the big retro dance numbers.

"I was nervous, but then I showed them all the stills and they've already had their mortification moment about me wearing spandex.

"We have to get over this," she says with a laugh. "I can't wait for them to see it. It's as if we've all done it for our daughters.

"My son will be appalled, but I think he'll actually like it because he's a musician and he'll get a kick out of it.

"He appreciates music and this music is much trickier and more precise than I thought when I first sang along to the radio. I got all the lyrics wrong and some of the pitches, so working on it made me appreciate it so much more."

The cast certainly had to work hard to get all the songs - and dance moves - perfect. Initial filming took place on the 007 stage at London's Pinewood studios, where a mock-up of Donna's Greek village was built, before they transferred to the Greek islands.

"Voulez Vous goes by like this in the movie," says Meryl, snapping her fingers, "but it was so hard to get those steps right.

"We worked on it three weeks before we began shooting. It was everybody's bete noire - well, it was for all the non-dancing actors, which is to say all the actors!"

At this point Meryl spontaneously breaks into a rendition of the catchy tune, whilst swinging her arms and breathing heavily to show how strenuous it was.

"It goes so fast and there's 150 people on set and it's the only number where everyone's dancing at once - the whole cast and every dancer in London I think!

"It was really scary fast, they played those disco lights eight hours a day and the migraine set in, but we couldn't wait to get there in the morning and do it again cause it was so fun!"

As well as the big numbers Donna sings with the cast, Meryl also sings a duet - SOS - with Pierce Brosnan and then sings The Winner Takes It All to him just before Sophie's wedding.

She says: "I've sung all of these songs about 70,000 times from starting in my closet, which was the only place my family would allow me to practise, all the way to Pinewood and the place in Holland Park, London, where we were living. Those poor neighbours!"

"But I never got sick of singing the songs. Never, never, never. In my drama school, they used to use Abba to rev everybody up for dance class, because you just can't not be excited when it starts.

"They were very generous with letting us own the songs, as long as we were exact on the words and the timing," she adds.

"There's so many great songs, but it wasn't hard work, it was a joy to sing this."

After nine weeks at Pinewood, the cast headed to Greece to film on location on the islands of Skiathos and Skopelos.

Meryl said the transition wasn't too hard in terms of filming, but admits: "Greece was nicer!" However, it was the lengthy Pinewood shoot that helped the cast bond, she says.

"People who are in plays get to have that experience, whereas for most movies people fly in, do their bit and fly out. But because we were incarcerated in that barn, trying to learn Voulez Vous for three weeks before shooting started, that's all we talked about.

"Colin was so worried, Stellan was beside himself and Pierce was drenched in sweat everyday, but we all bonded over it. We were a company and we lived together. But they saved the best part of it to the end, when we went to Greece and they put us up in the most beautiful places."

MERYL STREEP: A LIFE IN FILMS

Kramer vs Kramer (1979)

Meryl was cast alongside fellow Hollywood stalwart Dustin Hoffman - and both won Oscars - for this tear-jerker about a divorced couple who fight for custody of their son.

Sophie's Choice (1982)

She won her second Oscar for her portrayal of a survivor of the Nazi concentration camps who finds a new life and love (Kevin Kline) in New York.

Silkwood (1983)

Meryl teamed up with Kurt Russell and bagged another Oscar nomination for playing Karen Silkwood, a worker at a nuclear plant who blew the whistle on its poor safety record.

Out Of Africa (1985)

Another year, another Oscar nomination for another gritty drama. This time Meryl starred alongside Robert Redford to tell the true story of Karen Blixen - a Danish woman who ran a farm in Africa.

The Devil Wears Prada (2006)

Meryl scooped her 14th Oscar nomination for her role as New York fashion magazine editor Miranda Priestly who makes life hard for her young protege (Anne Hathaway).