J.K. Simmons didn't wear a fat suit for his role as Stu Kopenhafer. He gained more than forty pounds.
In an interview on Episode #3.100 (2009) Renée Zellweger said the temperatures in Winnipeg, Manitoba were so cold during filming (as low as -55° C or -67° F), the camera could only run for up to one minute per take, to prevent the heat generated by the camera's electric motor from cracking the icy lens.
The pictures on Blanche's desk are photos of Siobhan Fallon Hogan's actual family.
Director Jonas Elmer left this movie halfway during post-production. Disputes between him and producers led to the exit. He originally aimed for this movie to appeal to a mature audience, which the producers originally supported. When they changed their mind midway during production, Elmer decided to leave this movie behind. He has deliberately decided not to work in the U.S. again.
In the trailer, Lucy loses control while driving on the ice lake, hitting several ice huts. This scene doesn't appear in the final cut.