Entertainment Weekly, Us Weekly and People magazine have all reported the news, but no official announcement from Beyoncé or Jay-Z themselves. The date of birth and gender of the babies are not yet publicly known.
Not too long ago, on twitter, Beyoncé’s dad posted a happy birthday message on twitter (seen below).

Speculation about the twins’ birth had grown in recent days after a woman was photographed entering a Los Angeles hospital on Friday holding a card that read “B + J”.

In the meantime, congrats to Bey & Jay, and congrats to Blue Ivy on becoming a big sister. You can relive the beauty of her pregnancy shoot here.