Jay-Z has revealed that new mum Beyoncé, 30, suffered a miscarriage before giving birth to Blue Ivy Carter.
In his latest song, Glory, which was released yesterday, Jay-Z spoke of the agony of losing a baby.
The couple are said to be relieved and "in heaven" following the birth of the baby girl, although the rapper's new track tells of the heartbreak the couple experienced the first time Beyoncé was pregnant.
The song, which was posted on his social website Life and Times, features the lyrics: "Last time the miscarriage was so tragic/We was afraid you'd disappear/But nah baby you magic."
Glory also features Blue Ivy Carter crying at the end of the track, which was produced by music giant Pharrell.
The song continues with: "The most amazing feeling I feel, words can't describe what I'm feeling for real/Baby, I paint the sky blue, my greatest creation was you."
"You're the child of destiny/You're the child of my destiny/You're my child with the child from Destiny's Child."
The couple have denied reports that Blue was born by Caesarian.
The baby was "delivered naturally at a healthy 7lb and it was the best experience of both of our lives", they said.
The couple are believed to have spent $1.3 million (£840,000) on security renovations on an already expensive hospital suite to protect their baby. Work included a bullet-proof door and around-the-clock security.