Billy Crystal's Monsters University graduated top of the U.S. box office over the weekend after raking in $46.1 million (£29.7 million) in ticket sales.

The animated family film beat Melissa MCCarthy and Sandra Bullock's cop comedy The Heat, which debuted at number two with earnings of $40 million (£25.8 million).

Brad Pitt's zombie thriller World War Z was in third with takings of $29.8 million (£19.2 million), while Channing Tatum and Jamie Foxx's action epic White House Down came in a disappointing fourth place ($25.7 million/£16.6 million).

Superman movie Man of Steel rounded out the top five with $20.8 million (£13.4 million).