United Kingdom, July 10 -- Jesy Nelson broke down in tears and admitted her "heart was broken into a million pieces" after sharing an update on her twin daughters on Instagram.

The former Little Mix star gave birth to Ocean and Story - her first children with her ex-fiance Zion Foster - last year and doctors later confirmed both girls were battling SMA Type 1, a rare, inherited genetic disease that damages motor neurons in the spinal cord.

While there is no cure for the disease, there are things that can be done to help slow down the progression.

In a video on her Instagram Stories, Jesy admitted that while she knows she has to put her girls in the devices meant to help them, it's heartbreaking to do so when there's a heatwave, like th...