Beyonce Knowles is pregnant, according to multiple sources.

The 'Grown Woman' singer - who welcomed her first child, daughter Blue Ivy Carter, into the world in January 2012 - is said to be expecting again with her rapper husband Jay-Z.

E! News claims ''multiple sources'' close to the star told them Beyonce, 31, is pregnant with the couple's second child.

Speculation about Beyonce's pregnancy first started following her attendance at the star-studded Met Ball earlier this month.

The pop superstar is said to have ''carefully'' hidden her baby bump in a high-waisted Givenchy gown.

She was then forced to cancel world tour performance in Antwerp, Belgium, after doctors advised her to rest ''as a result of dehydration and exhaustion''.

Beyonce recently admitted she would love to give her 16-month-old daughter a sibling, because she enjoyed such a close relationship with her younger sister Solange Knowles, 26, when they were growing up.

She said: ''I would like more children. I think my daughter needs some company. I definitely love being a big sister.''

When pressed on when she may have another child, she added: ''At some point, when it's supposed to happen.''