Beyonc Knowles and rapper husband Jay-Z left baby Blue Ivy at home for date night on Sunday.

The new parents would normally have attended the Grammy Awards but decided to stay closer to home having just welcomed their daughter into the world five weeks ago.

Us Weekly reports that the music superstar couple didn't stay in to watch the annual music show, but went out for a pizza instead.

"They were just like a regular couple talking and whatnot," a witness told the publication adding that many of the other customers didn't even realise they were there.

"They were sitting in front of the place closer to where they make the pizza."

The loved up twosome, who have been married for nearly four years, took a luxury Maybach car from their Tribeca home to the Carroll Gardens area of Brooklyn where they had the Italian treat at Lucali pizzeria.

When they got up to leave Beyonc, ensured to say goodbye to the owner and the waitress and Jay-Z thanked fellow patrons who congratulated him on the birth of Blue.

The couple decided not to sell pictures of their daughter but instead posted images of their gorgeous little girl online inviting people to "share in their joy."

"B really, really thought about this," her friend and stylist June Ambrose told Us. "She really wanted to do it this way. She just couldn't imagine selling pictures of her baby."