Remember the evergreen pop tune When Will I See You Again?
It has been covered by countless acts over the last few decades and the original group behind the song, American vocal trio The Three Degrees, are still touring the world more than 50 years after they formed in 1963.
Listed in the 2006 Guinness World Records book as the longest running female vocal group in history, the current line-up, still a trio, will perform at the Esplanade Concert Hall on Monday.
The secret to their longevity in the music business is simple, says Valerie Holiday, who has sung with the group since 1967.
"I think our music is universal, the songs are not dated," she says in a telephone interview from Japan, where the trio were on tour.
BOOK IT / THE THREE DEGREES LIVE IN CONCERT
WHERE: Esplanade Concert Hall
WHEN: Monday, 7.30pm
ADMISSION: From $38 to $128. Go to www.sistic.com.sg or call 6348-5555
"The stories that each one tells are just as relevant today as when we recorded them. The message that the music gives you is the same, so it's not restricted to a time frame, which allows it to be continuous."
The line-up now also includes Helen Scott, who first sang with the group from 1963 to 1966 and rejoined in 1976, and Freddie Pool, who has been with the group since 2011.
When Will I See You Again, which the group released in 1974, has been covered by artists such as 1980s boyband Brother Beyond, alternative rock singer-songwriter PJ Harvey and synth-pop duo Erasure. Cantopop singer Priscilla Chan also did a bilingual version of the song in 1988.
The song's lyrics embody the universal nature of The Three Degrees' music perfectly.
"You will find yourself at one point in life asking that very question, whether it is your girlfriend, whether it is a family or friend," says Holiday. "I still love it, it is one of my favourites and I quite enjoy performing it in Japan because we sing it in Japanese."
The group's rotating cast - the original line-up comprised Fayette Pinkney, Shirley Porter and Linda Turner - have also achieved global hit songs such as Woman In Love and My Simple Heart, both from 1979, and Take Good Care Of Yourself from 1975.
The type of audience that they see at live shows has not changed much either, says Holiday.
"We've always been able to have an audience from six to 90 and that seems to still be the same.
"People will come and bring their younger children or siblings or their mother or their grandmother, so it's really nice. And because the music is not offensive, you don't have to worry about having a 16- or 12-year-old sitting in the audience. They can enjoy the show as well."
Their music has smitten even royalty - one of their most prominent fans is Britain's Prince Charles.
Not only were The Three Degrees invited to perform at his 30th birthday party in 1978, they also entertained the guests at the pre- wedding party before his marriage to the late Lady Diana in 1981.
Asked if the group have met him again recently, Holiday replies with a laugh: "This was years ago. In our hearts, we hope that we are still his favourite group. But no, with our schedule and his, we're not able to meet up."