Louis Tomlinson’s sister Félicité has been found dead aged 18 at her home after suffering a suspected heart attack.
The Instagram star and aspiring fashion designer reportedly collapsed at her apartment in Earl’s Court, west London, on Wednesday.
Her death is being treated as "unexplained”.
One Direction star and X Factor judge Louis has been left “devastated and distraught”, The Sun reported.
He praised his sister as "loveable, caring, bright and beautiful," sources close to the singer told the newspaper.
It comes after his mother, Johannah Deakin, died of leukaemia aged 43 in 2016.
Louis pulled out of tomorrow night's Comic Relief, where he was due to perform his new single live as one of the headline acts.
The song, called Two Of Us, is a tribute to his mother.
The Standard has approached representatives of the singer for comment.
Police and the London Ambulance Service rushed to the teenager's home just before 1pm. Despite efforts of paramedics, Félicité was pronounced dead at the scene.
A person who was with her had called 999.
In a statement, Scotland Yard said: "Police were called by London Ambulance Service at 12.52 on Wednesday, March 13 to a residential address... following reports of a female in cardiac arrest.
"A female believed to be aged 18 was pronounced dead at the scene.
"A post-mortem examination will take place in due course."
