"We would like to share our love and happiness".
In true Beyonce fashion, she announced her pregnancy with a surprise Instagram post in February, dropping a picture of herself draped in a light-green veil and surrounded by flowers.
The gender of the twins is unknown and no further details have been revealed, and Beyonce and Jay Z have not confirmed the birth. We have been blessed two times over.
The photo broke an Instagram record, quickly becoming the most "liked" post on the social media platform.
Beyonce and Jay Z are usually tight-lipped about their personal lives and waited years to release footage of their wedding and weeks to confirm the birth of daughter Blue Ivy, who is now 5.
Beyonce gave birth to her first child, Blue Ivy Carter, on January 7, 2012, a Saturday.
Thanks to a successful world tour and the hit album Lemonade, she was the second highest-paid entertainer in the year ended June 1, earning US$105 million (S$145 million), Forbes said. She pulled out of her headlining spot at April's Coachella music festival in southern California, however, on the advice of doctors.
The pop star shared frequent updates on her pregnancy in recent months. She has been spotted courtside at basketball games and at awards shows with her baby bump since the February announcement.