"You're my favourite" may be phrase now synonymous with Bruce Forsyth and Strictly Come Dancing but it's been used before - by Prince Charles to The Three Degrees.

The heir to the British throne is a big fan of the American group and even invited them to his 31st birthday party and the celebrations of his marriage to Princess Diana in 1981.

"It was interesting and exciting and an honour," says Valerie Holiday.

"It was very surreal coming out of Buckingham Palace at 4am and sometimes you think it's a fairytale and you have to pinch yourself to prove you were really there.

"The invitations are on my wall though."

Despite many line-up changes since the group's conception in 1963, Valerie has been with them since 1967 and is joined on stage these days by Helen Scott, who returned to the group in 1976 having been part of it between 1963 and 1966 and Cynthia Garrison, who joined in 1989.

They didn't break through until the mid-1970s though with songs such as When Will I See You Again and Dirty Ol' Man but have been touring ever since, something Valerie puts down to the hard work they put in at the start of their careers.

"It has to do with the base of the group when we were managed by Richard Barrett back in the late 1960s," she says.

"He was very strict on us because we were quite young and he taught us to work first and to live your life next, he made sure everything was polished.

"We knew the competition was good and we had to be unique and different.

"That uniqueness has always been about and has sustained us, even now the standard of the group is very high, which is why we are still here even without producing records."

Despite the inevitability of age creeping up on of the three, Valerie has no intention of quitting anytime soon.

"I plan on going on for as long as I possibly can," she says.

"We all enjoy it and the response we get from people and the pleasure you feel at different times makes you know there's a need for a happy period at the moment.

"If we can add one hour of enjoyment to a persons day it's a pleasure so we will be going on and on and on like the energizer bunny."

The Three Degrees, Fairfield Halls, Park Lane, July 24, 8pm, £19.50. Call 020 8688 9291 or visit fairfield.co.uk.