The `Halo` singer and rapper husband Jay-Z welcomed their first child together at the Lenox Hill Hospital in New Yorkon 07.01.11 and have decided to name her Ivy Blue Carter, according to E! news.
Jay - real name Shawn Carter - is said to have been by his wife`s side as she gave birth and they are thought to have paid $1.3 million to rent out the entire fourth floor of the hospital.
Pop singer and friend to the couple Rihanna tweeted: "Welcome to the world princess Carter! Love Aunty Rih (sic)."
Music mogul Russell Simmons closely followed, writing: "Congrats to my good friends Beyonce and Jay-Z (sic)."
Beyonce, 30, reportedly checked into the hospital under the name Ingrid Jackson and friends of the couple were seen bringing bottles of red wine and food to celebrate after the birth.
Beyonce and Jay, 42, were married in 2008 after dating for six years and she revealed she was pregnant at last year`s MTV Video Music Awards in August.
Speaking about her pregnancy last December, Beyonce said: "It`s exciting! I know it`s gonna be difficult at times. I know that, like my mother, I`m gonna get on my child`s nerves but I`m just ready! I`m ready for the next chapter."