For the last man on Earth, Will Smith sure has a lot of friends. The Warner Bros. tale "I Am Legend," starring Smith as a plague survivor who may be the last living human, debuted with $76.5 million, the biggest December opening ever and a personal best for one of Hollywood's top box-office champs, according to studio estimates Sunday.

"It's no wonder Will Smith feels so lonely. Everyone else on Earth is in the movie theater," said Paul Dergarabedian, president of box-office tracker Media By Numbers.

The 20th Century Fox family flick "Alvin and the Chipmunks," starring Jason Lee in a big-screen take on the cartoon critters, opened a strong No. 2 with $45 million. The two films combined to give Hollywood a year-end surge after a drowsy fall season.

"Forty-five million acorns," said Chris Aronson, senior vice president for distribution at 20th Century Fox. "Chipmunks are diurnal animals and they do hibernate, but not right now."

Overall business soared, with the top 12 movies taking in $153.6 million, up 39 percent from the same weekend a year earlier, when Smith also was No. 1 with a $26.5 million debut for "The Pursuit of Happyness."

The previous No. 1 movie, New Line Cinema's fantasy "The Golden Compass," nose-dived in its second weekend, coming in third with $9 million, down a dismal 65 percent from its less-than-expected $25.8 million debut a week earlier.

"The Golden Compass," which cost $180 million to produce, has done $90 million so far overseas but has proven a dud domestically with just $41 million.