A source said: "They wanted another child and after a few years of trying, it’s a great feeling. Beyonce's very happy."
The couple were thought to have gone through some tough times recently but they are now much stronger and realise what a "great team" they make.
The insider told People magazine: "They are a power couple and they make a great team. They know they are more interesting together than apart."
The pair announced the happy news they were expecting twins with a post on Instagram, where the 35-year-old singer - who already has five-year-old daughter Blue Ivy with her husband - showed off her burgeoning baby bump.