Beyonce's baby is Jay-Z's Glory
Jay-Z has confirmed the birth of "the most beautiful girl in the world" - his newborn daughter - with a rap.
The song Glory made its debut on his social website, two days after his wife Beyonce reportedly gave birth to a daughter, Blue Ivy.
Representatives of the stars repeatedly refused to confirm the birth had occurred, but Jay-Z's song gives fans the details.
It says: "You're my child of a child from Destiny's Child."
In the song, Jay-Z talks about where the child was conceived (in Paris) and even reveals that Beyonce had a miscarriage at one point: "Last time the miscarriage was so tragic/We was afraid you'd disappear/But nah baby you magic."
The song's refrain is: "The most amazing feeling I feel/Words can't describe what I'm feeling for real/ Maybe I paint the sky blue/My greatest creation was you. You. Glory."
The sound of a baby's cries - perhaps Blue's - ends the song. The song says it features "B.I.C." - which would be the initials of Blue Ivy Carter
Celebrities close to the couple have tweeted congratulations.
Beyonce's sister Solange Knowles tweeted on Sunday morning: "The most beautiful girl in the world."
Beyonce's close friend Gwyneth Paltrow also tweeted: "Welcome to the world Blue! We love you already."