The four Sledge sisters don’t usually get together to sing unless there is a special occasion. Last time it was for a tribute to Michael Jackson in Las Vegas where they were joined by Clifton Davis for a duet of the Jackson 5 classic he wrote, Never Can Say Goodbye. Before that it was to host the Pennsylvania inauguration ball to celebrate another iconic American, Mr Barack Obama.

But aside from celebrity ceremonies and incoming presidents (they also sang at the White House for the Clinton family), full Sledge appearances have been sparse despite the occasional new release.

“We’re really excited about this new tour,” says Kathy, the youngest sibling who speaks to me from her Philadelphia home.

“I love England. Goodness, I have played hundreds of shows in England, and our first hit, Mama Never Told Me, was in England when I was only 13.

“A friend just sent me some archive pictures via the amazing world of Facebook. I was just like ‘Wow’, I can’t believe how young I was.”

We all know the perils of stardom at a young age, a life in spotlight. But what is it really like to be catapulted to stardom at only 13?

“Well, we were raised by our mum – a single parent and a dynamic woman. We never planned to be a group.

Yes, we sang and we harmonised at home, but I remember someone’s band had walked out on them just two weeks before a show and we were asked to do it.

“We sang and got paid. I was like ‘Wooah, they’re paying us for this?'. It was a way of helping our mum pay the bills, but I feel like it was destiny.

Little things like our name being mistaken – we were the Sledge Sisters, but the DJ introduced us wrong. From then on, I knew it was meant to be.”

Kathy recalls the time as a whirlwind, characterised only by work. The group toured with the Jacksons in 1979 and had worldwide smashes with We Are Family and He’s The Greatest Dancer.

“I was very driven for such a young age but, honestly, I loved what I was doing. Now, thinking about it, we all took the death of Michael Jackson hard. I really relate to his passing, it has made me reflect.”

“I know about growing up on the road, the way you have to separate real life from stage life, but he couldn’t. He wasn’t allowed to. Michael was only eight and the stage was his only home. He was one of the kindest people I’ve ever met, but explosive on stage.”

Visitors to Concorde 2 for tonight’s show should expect vintage Sledge from the period they had disco go-to men Nile Rodgers and Bernard Edwards on production duties.

“Those two had a formula in their heart they knew worked, and we trusted them. With that formula you weren’t allowed to hear the songs until it was time to sing because they believed in spontaneity.”

We Are Family was done in one take and it still sounds natural.

“I didn’t understand it then but now I see it,” says Kathy.

“They had a sound, an amazing marriage between their songs, musicianship and singers. And that was that. The rest, I suppose, is history.”

*7pm, £20, 01273 673311