One Direction star Louis Tomlinson’s sister Felicite has died after suffering a suspected cardiac arrest aged 18.

The aspiring fashion designer died at her flat in Earl’s Court, west London, on Wednesday.

Her death is being treated as unexplained by police.

It comes after Tomlinson’s mother Johannah Deakin died from leukaemia in 2016 at the age of 43.

Louis Tomlinson Louis Tomlinson’s mother died from leukaemia in 2016 (PA)

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.”

A person who was with the teenager called 999, according to The Sun newspaper.

Felicite was well-known on social media and regularly shared posts with her 1.3 million followers on Instagram.

On January 30, she posted a picture of a row of tattoos on her forearm, which she said were the initials of all her siblings.

Her last post came just four days ago.

It is understood that Tomlinson, who is reportedly in London for a now-cancelled appearance on Friday night’s Comic Relief, was told of her death on Wednesday.

The siblings’ mother died at the Royal Hallamshire Hospital in Sheffield on December 7 2016 after being diagnosed with leukaemia earlier that year.

Following her death, Tomlinson released the song Just Hold On – his debut solo single – in her honour and he performed it on The X Factor just days later.

At the time he described the performance as “harder than I ever imagined”.