This is so tragic.

One Direction singer Louis Tomlinson's 18-year-old sister Felicite passed away suddenly from a suspected heart attack yesterday in London, TMZ first reported.

The social media influencer collapsed in her flat and a friend called 911, but paramedics were unable to recessitate her and she was pronounced dead at the scene. Sources say they had no prior knowledge of any heart conditions or other factors that may have contributed to her death.

Upon learning the sad news, the singer pulled out of a scheduled BBC charity show, Comic Relief, and rushed to be with his family. Louis is said to be "devastated," as he and his sister were super close.

As if this situation wasn't bad enough, Tomlinson lost him mom Lottie to leukemia back in 2016 when she was just 43-years-old.

Gone too soon.