Beyonce pregnant US pop sensation Beyonce Knowles is expecting her first child...

U.S. pop sensation Beyonce Knowles is expecting her first child with rapper husband Jay-Z, Us Weekly reported Wednesday.

The Grammy Award-winning artist is said to be in her first trimester of pregnancy, which reportedly came as something of a surprise.

"B was shocked. She loves kids, but she wasn't ready to be a mother just yet," said a source close to the singer.

VIDEO: REPORT SAYS BEYONCE IS PREGNANT

Another insider said Beyonce, 29, believed

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Beyonce is reportedly pregnant with her first child.

The couple have not yet confirmed the news and Beyonce has been subject to false pregnancy rumors in the past, notably in March when U.S. website Mediatakeout reported Jay-Z was

Regardless of this, Wednesday's report quickly took Twitter by storm.

"Please let little Jay Z and Beyonce look JUST like the Mommy," one fan wrote, as another added,

Celebrities were also starting to pass on congratulations to the couple.

"Jay has been all about family since I met him, and he's always going to be," record executive Kevin Liles, a longtime friend of the couple, told Us Weekly.

Beyonce married Jay-Z, 40, in a low-key ceremony in 2008.

They are notoriously private about their relationship, but Beyonce made no secret of her desire to have kids in the past.

"I definitely want to have a child, but I know from my nephew it's a lot. I hope that those things will just happen naturally. I still haven't had time to relax," she told Allure magazine earlier this year.

Beyonce's nephew is Daniel, the son of her sister Solange Knowles, who said Beyonce would make a