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Jay-Z has confirmed the birth of "the most beautiful girl in the world" -- his newborn daughter -- with, what else, a new rap!

The song "Glory" made its debut on Jay-Z's site Monday -- two days after he and Beyonce reportedly gave birth to a daughter named Blue Ivy.

Reps for the superstars repeatedly declined requests for comment from The Associated Press about whether the birth had occurred, as first reported by E! News. But Jay-Z's song gives some details, including this nugget:

"You're my child of a child from Destiny's Child."

("Sweet Caroline" it ain't.)

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Celebs close to the couple have also tweeted congrats: Beyonce's sister, Solange Knowles, tweeted Sunday morning: "The most beautiful girl in the world," while Beyonce's close friend Gwyneth Paltrow also tweeted: "Welcome to the world Blue! We love you already."

Meanwhile, back at Beyonce's hospital in New York, everything is not so peachy keen. Fellow new moms and dads there are hopping mad at the extra security measures taken by the star couple and Lenox Hill Hospital to keep out prying eyes.

Sources at Lenox Hill tell TMZ some moms at a breastfeeding class there are griping about the way they've been treated, saying they feel "neglected" by hospital staff. They're so peeved they may even sue Lenox Hill.

"Someone at the hospital should be protecting us patients," the source told the website.

Jay-Z and Beyonce paid a reported $1.3 million to have a whole floor of the hospital put on lockdown, and even booted some new parents out of the neonatal intensive care unit (NICU) -- on the same floor as Beyonce's delivery "suite" -- so the pampered songstress and her party could come and go unencumbered.

"They just used the hospital like it was their own and nobody else mattered," raged new dad Neil Coulon, whose efforts to see his premature, newborn twins in the NICU were disrupted. "They locked us into the NICU and would say, 'You can't come out to the hallway for the next 20 minutes.' When I finally was able to go back out, I went to the waiting room and they'd ushered my family downstairs!"