Louis Tomlinson’s sister Felicite has died at the age of 18.
Emergency services attended a residence in Earl’s Court after reports of a female in cardiac arrest.
However the 18-year-old was pronounced dead at the scene despite extensive efforts to resuscitate her.
In a statement, the London Ambulance Service said: “We were called at 12.51pm.
“We sent two ambulance crews, a single responder in a car and an advanced paramedic to the scene.
“Sadly, despite efforts of our medics, a person died.”
Police said officers arrived at the west London home shortly after ambulance crews.
At this stage the death is being treated as unexplained and a post-mortem is due to take place.
Felicite, an aspiring fashion designer, collapsed after a suspected heart attack inside her apartment, The Sun reports.
A person who was with her is said to have called 999.