BABY-ONCÉ finally has a name — Blue Ivy Carter.

Music royalty Beyonce and Jay-Z welcomed the baby girl in a private wing of Lenox Hill Hospital, the E! network reported Sunday. The baby’s name was originally reported by E! as Ivy Blue.

Music mogul Russell Simmons also confirmed the arrival of the bundle of joy, tweeting “congrats to my good friends Beyonce and Jay-Z.”

Gwyneth Paltrow, a good friend of the music moguls, tweeted, “Welcome to the world Blue! We love you already.”

Rihanna added her congratulations as well, writing “Welcome to the world princess Carter! Love Aunty Rih.”

A very pregnant Beyoncé had checked into the upper East Side hospital on Friday night under the name “Ingrid Jackson,” a hospital staffer told the Daily News.

Beyoncé and her hip-hop hubby, whose real name is Shawn Carter, rented out the hospital’s entire fourth floor for $1.3 million, the employee said.

On Saturday night, people were seen bringing bags of takeout and a dozen bottles of red wine onto the heavily guarded hospital wing.

After 11 p.m., even doctors and nurses were barred from entering the fourth floor, prompting one doc to complain that he had patients to see.

In an effort to keep images from leaking to the public, hospital workers placed tape over security cameras and are forcing employees to turn in cell phones when they arrive for their shifts, a source said.

Several security guards were spotted patrolling the perimeter of the hospital Saturday night.

A Lenox Hill staffer confirmed that a patient named Ingrid Jackson was in a “labor room.”

Reps for the power couple did not return requests for comment.

The 30-year-old singer was last seen Thursday when she was photographed leaving a Manhattan apartment building wearing hip-hugging jeans, gold heels and a patterned scarf masking her belly.