The Nolan sisters are to perform with their sibling Denise for the first time in 43 years amid fellow member Linda's cancer battle.
Denise, 69, departed the group in 1978 to pursue a solo career, just as they were beginning to make an impact on the U.K. charts, and had never rejoined her sisters in the group despite several incarnations.
She will join Coleen, 56, Anne, 70, Maureen, 67, and Linda, 62, to perform on a cruise ship during a second series of their show The Nolans Go Cruising. Linda is heading off on the trip despite fighting secondary breast cancer that has spread to her hip and liver.
The brave star told The Mirror: "We had so much fun on our last trip and it's great all five of us are doing it this time around!"
Coleen added: "I can't wait to be setting sail with my sisters again, letting our hair down and exploring the UK coast together."
The announcement comes shortly after the I'm in the Mood for Dancing hitmakers planted a tree in memory of their late sister Bernie's death, who died of breast cancer eight years ago on Sunday.
Last month, Maureen revealed she'll be replacing Linda in the musical Girls Just Wanna Have Fun, after doctors told the star that her incurable cancer meant she could not perform.
Praising Maureen for filling in, the courageous musician said: "I'm gutted that I can't do the tour. I was really excited but I know Maureen will do an amazing job. I'll be cheering her on in the wings."
Her sister explained that she was "delighted" to join the show but wished it was in less tragic circumstances.
Back in April, Linda revealed to OK! magazine that she is "scared of dying" as she had "so much to live for". She previously fought off cancer after a 2006 diagnosis but the disease returned a decade later.
Anne, the oldest Nolan, has also been diagnosed with cancer but said in December that cancerous cells had "disappeared" after a course of chemotherapy.
The Nolans Go Cruising airs on the Discovery+ streaming service.