Beyoncé welcomed her and husband Jay-Z's first daughter Ivy Blue Carter into the world yesterday (January 7).

The singer gave birth by Caesarean section at Lenox Hill Hospital, New York with Jay-Z present, according to reports.

The couple are said to have booked the entire fourth floor of the hospital, costing $1.3m (£840,000), while Beyoncé checked in under the name Ingrid Jackson.

Friends of the pair have taken to Twitter to send congratulatory messages since the news broke.

Rihanna tweeted: "Welcome to the world princess Carter! Love Aunty Rih."

Russell Simmons added: "congrats to my good friends Beyoncé and Jay-Z."

A spokesperson for the couple is yet to confirm the news and security at the hospital has apparently been tightened.

Beyoncé announced her pregnancy on stage at the MTV Video Music Awards last August.

Congratulations to them.