Mariah Carey and Nick Cannon celebrated their fourth anniversary with another milestone - becoming parents to a baby girl and boy.

Carey's representative, Cindi Berger, confirmed the births. The singing superstar gave birth today at 12:07pm EDT (1607 GMT) at an undisclosed hospital in Los Angeles.

Ms Berger said the baby girl was born first, weighing 5 pounds, 3 ounces (2.35 kilograms), and was 18 inches (45.7 centimetres) tall; her brother was next, at 5 pounds 6 ounces (2.44 kilograms), and was 19 inches (48.3 centimetres).

Ms Berger said the couple has not named the children yet. Cannon drove Carey to the hospital in their Rolls-Royce Phantom. Ms Berger said the 41-year-old Carey, who had gone through false labour, was calm, thinking that it was another false alarm.

Meanwhile, the 30-year-old Cannon was so nervous he went to the wrong department at the hospital, and was guided to the maternity ward by a nurse.

"It was like right out of an 'I Love Lucy' skit," said Ms Berger, referring to the 1950s TV comedy.

Ms Berger said they were listening to Carey's We Belong Together after the children were born.

The couple are expected to renew their wedding vows tomorrow. The pair got married in 2007 after a whirlwind romance. They were the subject of endless baby rumours, and the couple actually were expecting shortly after their marriage, but Carey had a miscarriage; they did not reveal the miscarriage until she announced her pregnancy last autumn.

The couple plan to live a bi-coastal life, and have luxurious nurseries in both New York and Los Angeles.

As far as more children, Carey recently declared she's done.