The Spice Girls have been praised as "hard-working, ambitious and highly-motivated".
Legendary British jazz star Pepi Lemer, who was the Spice Girls' original vocal coach, admitted there were plenty of tears as she taught the girls to work together as a group but praised them for their determination to succeed.
She said: "My impression of them was, and always has been, of a hard-working, ambitious and highly-motivated group, which held them in good stead.
"They came from disparate backgrounds, had different personalities and were different vocally. Most had not left home, so were missing their families and they had to learn to curb any egos and find a way of living and working together.
"They were learning as a group, not as individuals, so I had to fit in to their needs. My time was spent very intensely with them. "As you can imagine, they were learning to sing as a group - so there were quite a few tears!"
Victoria Beckham has gone on to become a celebrated fashion designer and Pepe, 72, is not surprised because she says Posh Spice was stylish from the very start.
She explained: "At the start, the girls had no money for clothes so I used to bring my cast offs for them. Victoria showed little interest, but I don't blame her - she had taste even then!
"I remember coveting a handbag Victoria had back then. I think it was from Top Shop. Oh, how things have changed."
The group - which is also comprised of Geri Horner, Mel B, Mel C and Emma Bunton - is celebrating 20 years since the release of first single 'Wannabe' and Pepe is proud of their success.
She said: "I was part of their first team and we all feel so proud of what they have achieved."
Pepi - who has also worked with The Beatles, Rolling Stones and Madonna - will take to the stage at PizzaExpress Jazz Club in London's Soho on June 27 after successfully beating cancer of the oesophagus.
She said: "This live show - and each and every one that follows - is a triumph over the impossible... because I never thought I would live to see them."
Pepi will perform songs from her album 'Back2Front', which is her first ever solo record.
For more information, go to www.pepilemer.com.
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