Much of that was due to the on-screen romance for the characters played by Shia LaBeouf and Megan Fox, who were relative unknowns when the first movie came out.

With a $13 million weekend, Disney and Pixar Animation's "Up" became the year's top-grossing film domestically at $250.2 million. It surpassed Paramount's "Star Trek," which did $3.6 million over the weekend to hit a $246.2 million total.

The reign of "Up" at the top of the year's box-office chart will be short-lived, though. The "Transformers" sequel should shoot past it in a matter of days.

The Warner Bros. melodrama "My Sister's Keeper," with Cameron Diaz and Abigail Breslin, had a so-so debut, coming in at No. 5 with $12 million. Breslin plays a daughter conceived as a donor for her older sister, who has leukemia.