Along Came Polly is at number two in the US

The film, starring Ashton Kutcher, took $17.1m (�9.4m) in its opening weekend, with Along Came Polly in second place with takings of $16.6m (�9.1m).

Romantic comedy Win A Date With Tad Hamilton! entered in third place, with $7.6m (�4.2m) in ticket sales.

Big Fish slipped to fourth, a place in front of Golden Globes winner The Lord of the Rings: The Return of the King.

Top five movies 1. The Butterfly Effect 2. Along Came Polly 3. Win A Date With Tad Hamilton! 4. Big Fish 5. The Return of the King

The third Rings film is in its sixth week in the top 10, taking another $6.8m (�3.7m) over the weekend, according to initial figures from US box office monitors Exhibitor Relations.

The movie has now taken about $337m (�187m) in North American cinemas alone.

Steve Martin comedy Cheaper by the Dozen, about a family with 12 children, was sixth with $6.6m (�3.6m).

US civil war drama Cold Mountain, which won only one of its eight Golden Globes nominations with Renee Zellweger getting best supporting actress, was seventh with $5.3m (�2.9m).

Motorcycle action film Torque was eighth with $4.4m (�2.4m), while Diane Keaton and Jack Nicholson's film Something's Gotta Give was ninth with $4.1m (�2.2m).

Director Clint Eastwood's crime thriller Mystic River rounded off the top 10 with $3.1m (�1.7m).