Music mogul Russell Simmons has also confirmed the arrival of the bundle of joy, on Twitter.
"Congrats to my good friends Beyonce and Jay-Z," the New York Daily News quoted him as tweeting.
According to a hospital staffer, pregnant Beyonce had checked into the upper East Side hospital on Friday night under
the name "Ingrid Jackson".
Beyonce and her hip-hop hubby, whose real name is Shawn Carter, had apparently rented out the hospital's entire fourth floor for $1.3 million.
On Saturday night, people were spotted bringing bags of takeout and a dozen bottles of red wine onto the heavily guarded hospital wing.
Us Weekly reports that an eyewitness saw Beyoncé's sister Solange and parents Tina and Mathew Knowles at the hospital holding 'flowers with pink balloons and silver and black ribbons.'
Jay-Z was also seen walking through the hospital halls looking 'happy' an observer said.
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