The couple already have a daughter, Blue Ivy, aged five.

There has been no official confirmation of the birth from Beyonce and Jay-Z themselves.

Grab of Beyonce's Instagram post with picture of her and the announcement

Photo: Beyonce announced her pregnancy in an Instagram post in February

Other photos Beyonce posted after her pregnancy announcement showed her swimming under water, reclining on a bed of roses and sitting naked on a floral throne.

In one, the ‘Lemonade’ singer stood naked, cradling her belly with one hand and a breast with the other, next to the sculpted head of an Egyptian ruler.

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”.

Beyonce is the most-nominated star in the history of the Grammy awards, and her album Lemonade was the world’s best-selling record of 2016.

She had been due to headline the Coachella music festival in California in April, but pulled out on her doctor’s advice.

The twins’ birth – if confirmed – comes only days after actor George Clooney and his wife Amal welcomed their own set of twins, Ella and Alexander.