The 36-year-old singer growing baby bump became too big to ignore during the European leg of the couples' On The Run II tour.
'Beyonce's inner circle think she might be having twins,' a source tells the US publication.
The couple are already parents to daughter Blue Ivy, 6, and 1-year-old twins Rumi and Sir.
'They've been talking about having another baby, but two little buns in the oven would be an unexpected surprise.'
'Beyonce is feeling tired,' a friend spilled to Life & Style. 'But Jay-Z is by her side.'
'He's looking after his wife and making sure that she's getting plenty of rest on the road.
To further add to speculation the entertainer is pregnant, while performing in Rome earlier this month, the 22-time Grammy winner, 36, showed off a growing baby bump.
Concertgoers shared videos of Beyoncé dancing on stage to Bonnie & Clyde in a tight silver minidress.
At the end of the song, audience members recorded the singer rubbing her stomach and smiling at the audience before leaving the stage.
The couple are yet to confirm their happy baby news.
This article originally appeared on New Idea.