"They are literally superhuman, honestly."

Despite all the challenges the former Little Mix singer has faced since her pregnancy, she says her girls are "little superhumans" and will "defy the odds".

The singer welcomed her twin daughters, Ocean and Story, with her fiancé, Zion Foster, in May, though the girls arrived a little earlier than expected.

During her pregnancy, the former Little Mix singer was diagnosed with twin-to-twin transfusion syndrome (TTTS), which is a rare condition that can pose serious risks to one or both babies.

On January 4, Jesy took to her Instagram to announce that her baby girls have been diagnosed with SMA Type 1 or Werdnig-Hoffman illness, the most severe form of spinal muscular atrophy.

This disabling condition is lifelong and causes severe muscle weakness as well as severe breathing and swallowing issues.

Left untreated, the condition can be fatal.

Jesy explained in her video: “If it’s not treated in time, your baby’s life expectancy will not make it past the age of two.”

Jesy recently opened up about the tough blows the family has had to face on an episode of Jamie Laing's podcast Great Company.

Speaking to Jamie, she said: "I feel like I don't really matter anymore, like they are, like my whole heart and soul, and like I have to just get on with it.

"Before, things that seem now seem so just ridiculous to me that I used to worry about. I'd sit in bed, and I'd cry, and I'd feel sorry for myself, and I'd have days where I just wouldn't even get out of bed."

She added: "And now, I don't have a choice to do that, because I have to just get on with it. It's s**t. It's really f***ing s**t. But at the same time, I'm just still so blessed because my girls are, they are literally superhuman, honestly, like I look at them and every day they are happy, and I'm like, What have I created?

"The s**t that they've had to go through, and they're still happy and smiling, and I'm like, that almost thing gives me even more like strength to be like, well, what gives me the reason to be sad?"

The new mum heartbreakingly went on to say that if children with the condition go without treatment, they could die before the age of two.

She said: "It's not okay, but it is what it is, and I just have to accept it, and now just try and make the best out of this situation... And my girls are the strongest, most resilient babies, and I really believe that they are going to defy all the odds."