Jordin Sparks' 16-year-old stepsister has passed away.

The 28-year-old singer - who is expecting her first child with husband Dana Isaiah - asked her fans to pray for Bryanna Jackson-Frias last week as she was ''fighting for her life'' in hospital after suffering from complications from sickle cell anaemia, but their mother, Jodi Jackson, revealed on Wednesday (31.01.18) that her daughter had lost her battle.

Jodi wrote: ''Bry went peacefully to Heaven. I can't help to think [that] she's smiling just like this. Thank you all for your prayers.''

Sickle cell anaemia causes red blood cells to get stuck in small blood vessels, blocking blood flow and preventing oxygen from reaching tissues, and Bryanna had suffered with it throughout her life.

But Bryanna's death isn't the only tragedy to rock the 'Tattoo' singer this week, as she revealed another family member, known as Q, has also passed away, and she's mourning the loss of singer Leah Labelle and her husband NBA player Rasual Butler, who were killed in a car accident in Los Angeles on Wednesday.

In a moving tribute on Instagram, she wrote: ''Four Angels in a week. My heart is just so heavy & broken. I'm in shock, numb and feel everything all at the same time.

''Leah & Rasual (one of my closest friends and her amazing other half who also was a great friend), Bryanna (my step sister) and Q (my little cousin), you were such bright lights in this crazy world. You made everyone better just by knowing them. And your smiles made anyone's day better.

''The world is less sparkly without you in it. Rest In Peace and Power. I love you forever. Find Miles and hug him for me.

''Tomorrow is not promised to any of us. Don't ever skip a chance to tell someone you appreciate them or how much you love them. Please, please continue to cover their families and our family with thoughts and prayers. #unicornsdontdie #sicklecellsux (sic)''