Back in 1999, the all female team behind musical "Mamma Mia!", based on songs by Swedish pop group ABBA, had no idea how successful their 'kitchen sink' show would be.

"When you're a producer, you just hope everything will work. So to be here 25 years (on) is a big milestone," producer Judy Craymer said, a few days before the musical celebrates it's landmark run in London's West End.

The drama of a mother and daughter with three possible dads has been seen in over 450 cities around the world, and led to two hit movies.

"The ABBA songs are the icing on the cake, but what we've done is we put the ABBA songs into context," Craymer said of the show, written by Catherine Johnson and directed by Phyllida Lloyd.

"We represent real people. It's not a fairy tale. It's very kitchen sink," said actor Mazz Murray, who plays mum Donna in the production at London's Novello Theatre. She hears audiences both weeping and laughing during the show, she added.

"I think 'Mamma Mia!' did change a dynamic. I think it's earned it's place in the cultural history of musical theatre," Craymer said, noting it offered something different and lighter to some of the other successful musicals of the time like Cameron Mackintosh's "Les Miserables" and Andrew Lloyd Webber's "Phantom of the Opera".

Reflecting on securing the use of the music, Craymer said that when she started suggesting to ABBA stars Benny Andersson and Björn Ulvaeus in the 1980s that a musical could be made from their songs "they'd probably moved on to other things".

"I think they thought that ABBA had kind of gone away... It wasn't till later in the nineties when things began to blossom, we began to move forward."

"What I love is that over the 25 years we have succeeded in bringing the show to new generations, bringing theatre to new generations, but also ABBA to new generations."

Coincidentally, while Mamma Mia! celebrates 25 years on April 6, ABBA are also marking 50 years since the release of their 1974 song "Waterloo", which brought them to global attention.

(Reporting by Sarah Mills Editing by Alexandra Hudson)