(CBS) After much anticipation and a slew of rumors, Beyonce and Jay-Z welcomed their baby girl, Blue Ivy Carter, over the weekend in New York City, according to reports.
The Grammy-winning singer checked into Lenox Hill Hopsital, on Manhattan's Upper East Side, on Saturday night under the name "Ingrid Jackson," but it didn't take friends and fans too long to catch on sending the Twittersphere into a frenzy.
Even celebrities joined in, welcoming the music power couple's first child.
"Welcome to the world princess Carter!" Rihanna, who is under Jay-Z record label, tweeted. "Love Aunty Rih."
"Welcome to the world Blue! We love you already," actress and good friend of the couple, Gwyneth Paltrow, wrote.
Fellow rapper Sean "Diddy" Combs also joined in, tweeting, "Congrats to Jay and B! And many more!"
Music mogul Russell Simmons added, "Congrats to my good friends Beyonce and Jay-Z."
The singer's sister, musician Solange Knowles, also took to Twitter to welcome her baby niece.
"The most beautiful girl in the world," she tweeted.
Beyonce and Jay-Z have not spoken out about their daughter, but there has been some speculation that the couple derived the name from the roman numeral for four, "IV," because of the significance of the number four in their lives, reports People magazine.
Beyonce's birthday is Sept. 4, Jay-Z's is Dec. 4, and the two married on April 4 in 2008.