Though no official announcement has been made, a friend of the couple told People magazine: "It happened earlier this [Friday] evening. Jay wanted it to be a really private affair – close friends and family."
The media swarmed outside Jay-Z's Tribeca apartment on Friday after news of their plans leaked.
Bouquets and speakers were seen being delivered for a party at the apartment, and a marquee was set up on the roof. Celebrity guests included Gwyneth Paltrow and Beyonce's Destiny's Child bandmates Kelly Rowland and Michelle Williams.
Rumours that the couple had taken out a marriage licence first emerged on Wednesday. They had been dating for six years.