'Devastated' Louis Tomlinson has paid tribute to his 'caring, bright and beautiful' sister Félicité, who has tragically passed away.
Félicité Tomlinson died on Wednesday in London of a suspected heart attack.
Félicité — also known as Fizzy — was attended to by medics after calls to 999 but sadly died at the scene.
Her death comes after the pair's mum Johannah died from leukaemia in 2016.
"Félicité was an absolutely adored young woman who was loved by Louis and her whole family," a family source told The Sun newspaper, adding that they had been left "totally devastated,".
"She had so many friends and was such a positive happy person. It's a massive loss to the world," they continued. "She was a loveable, caring, bright, passionate, popular and beautiful young lady."
A spokeswoman for the Metropolitan Police said in a statement: "Police were called by London Ambulance Service at 12:52hrs on Wednesday, 13 March to a residential address in SW5, following reports of a female in cardiac arrest.
"Officers attended. A female believed to be aged 18 was pronounced dead at the scene.
"Police are in the process of informing her next of kin. At this stage the death is being treated as unexplained. A post-mortem examination will take place in due course. Enquiries continue."
A London Ambulance Service spokesperson added: "We were called at 12:51pm yesterday [Wednesday, March 13] to reports of an incident in Earls Court.
"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 at the scene."
The tragedy follows Louis releasing his new single, Two Of Us, in tribute to his late mother.
He told BBC Radio 1's Newsbeat last week: "I'm not at the stage in my grief where I'm going to open the first verse and burst into tears.
"It was something I needed to get off my chest. I used to lean on my mum for a lot of things - anytime I needed advice on something she would be the first call I made."
It's been reported that Louis has pulled out of a planned performance of the song in tonight's BBC's Comic Relief live telethon.