The Irish singer is a generation-defining pop star. Her angst-shrouded music isn’t the highest-selling of her era but something about it feels significant, as if it had the same revolutionary reach as grunge did in the 1990s.

In the garden of her family home in Donadea, Co Kildare, Eilish Holton laughs as she chases her pet dog through the grass. Her smile masks a heartache that will be with her for life. It has been seven years since her Siamese twin sister Katie died just four days after surgery to separate them at Great Ormond Street hospital in London.

Mary and Liam’s daughters were born conjoined, sharing a bowel and legs, and were the focus of a television documentary that made headlines around the world. The girls were a source of joy to their parents, but also a source of anxiety because they could not be guaranteed a long and healthy life.

When the sisters reached school age the parents decided to have them separated. The operation was risky, and if the girls were not successfully separated they would die. But they were convinced the operation was the right thing for their children. Today, despite her loss, Eilish lives a life as normal as any 12-year-old’s with her big sisters Claire, Therese and Mairead and little sister Maeve, who has helped to fill the gap left by Katie. Her hobbies include singing and drawing, and she loves going to sleepovers at her friends’ houses.