Police are treating her death as unexplained.
Felicite and Louis lost their mum Johannah to leukemia back in 2016.
While nothing has been officially confirmed, TMZ is reporting that she was found deceased at her home in the Earls Court area of West London, England on Wednesday (March 13).
Court rules gun maker can be sued over Newtown shooting
Koskoff, one of the lawyers representing the families, told the panel of judges during oral arguments in the case in 2017. Leading gun control advocates such as Everytown for Gun Safety and the Brady Campaign applauded the ruling.
Celebrities - such as James Corden - sent their wishes to Louis Tomlinson following his sister's death.
Louis has not spoken publicly about this devastating news at this time, but he's reportedly "with family right now and he's devastated". "Love to you brother I'm so sorry and my prayers are with you".
McFadden wrote: "This is so sad".
Our deepest condolences are with Tomlinson and his entire family during this incredibly tragic time.
Beto O'Rourke calls for legalizing marijuana
Some later backed a super PAC that would play a key role in helping him defeat an incumbent Democratic congressman. Mr O'Rourke has represented Texas' 16 congressional district for three terms in the US House of Representatives.
In a statement to Metro.co.uk, the London Ambulance Service said, 'We were called at 12.51pm. A person who was with her at the time called 999 (the United Kingdom version of 911), and emergency responders quickly arrived on the scene.
The late star was well-known on social media and regularly shared posts with her 1.3 million followers on Instagram.
Her last post was just four days ago.
Louis was meant to perform at a Comic Relief event tonight in London, however, his apperance was cancelled by his publicist.
Residents warned as tropical cyclone Idai intensifies over Mozambique
A light aircraft has been dispatched with a team of specialists to Malawi to establish the exact humanitarian assistance required. This system turned around and once again came back to Mozambique Channel and received warmed waters resulting in strengthening.
American singer-songwriter Charlie Puth said he is sending "prayers" to Tomlinson and added: "I can't imagine how hard it is right now".