Guinea pigs break Harry Potter spell

The super-hero talking guinea pigs of "G-Force" broke the spell cast by Harry Potter to take the top spot at the North American box office, according to studio estimates issued today.

The Disney animated family feature earned $32.1 million in the United States and Canada, pushing "Harry Potter and the Half-Blood Prince" down to 2nd place with $30 million in its second weekend -- a 61 percent drop from its huge opening last weekend.

Romantic comedy "The Ugly Truth," starring Katherine Heigl and Gerard Butler, brought in a solid $27 million to take third place -- above expectations, distributor Sony Pictures said.

"Harry Potter and the Half-Blood Prince," the sixth film in the boy wizard franchise, had earned $159.7 million at the North American box office over its five-day opening period last week and set a global opening record of $396.7 million for distributors Warner Bros.

Industry watchers had expected the movie's box office gross to fall by around 50-60 percent in its second weekend but still retain its number one spot in the United States and Canada.