Called "Glory," the song released on Jay-Z's social website, LifeandTimes.com, followed the birth in New York on Saturday of daughter Blue Ivy Carter -- the first child of the music power couple.

"Last time the miscarriage was so tragic, we was afraid you disappeared," Jay-Z, 42, rapped midway through the song. He also spoke of "false alarms and false starts ... all the pain of the last time, prayed so hard it was the last time."

"The most amazing feeling I feel, Words can't describe what a feeling, for real, Baby I'll paint the sky blue, My greatest creation was you," the "Watch The Throne" singer rapped.

The baby's name, Blue Ivy Carter, was confirmed by fellow friend and actress Gwyneth Paltrow on Twitter and swiftly became a trending topic on the social media site.

Beyonce, now 30, and Jay-Z married in 2008, and the "Single Ladies" singer was reported multiple times in the past two years to have been pregnant.

But Jay-Z's lyrics in the new song Monday were thought to be the first time the couple had publicly spoken of previous pregnancies and a miscarriage.

In an official announcement Monday the couple said that Blue Ivy Carter was born Saturday.

"Her birth was emotional and extremely peaceful, we are in heaven. She was delivered naturally at a healthy 7 lbs and it was the best experience of both of our lives.

"We are thankful to everyone for all your prayers, well wishes, love and support. Beyonce & JAY Z," the statement said.

Beyonce revealed her baby bump at the MTV Video Music Awards in August, saying little but embracing her growing belly during an onstage performance.

The former Destiny's Child singer has forged a Grammy-winning solo career with hits such as "Halo." Brooklyn native Jay-Z has built a successful brand from his music career, Roc Nation music management company, Rocawear clothing line and investments.

His most recent collaboration, with Kanye West on the album "Watch The Throne," earned him four Grammy nominations this year.

(Reporting by Piya Sinha-Roy; Editing by Jill Serjeant)

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