Sarah Michelle Gellar

LOS ANGELES (Hollywood Reporter) - Recent box office champ "The Grudge," a haunted-house horror starring Sarah Michelle Gellar (news), is slated to be released Feb. 1 on DVD and will include a featurette that asks why people seek out fear at the movies.

Michael Gillis, who produced the 12-minute "Under the Skin" short for Sony, said he sought the answer from author and New York University professor Joseph LeDoux, who has spent more than 30 years researching fear.

After interviewing LeDoux and vast numbers of moviegoers, Gillis came to one conclusion. "What it all really boils down to is that we go to the movie theater to be afraid because it is only there in the dark where we can face our worst fears, seemingly alone, yet knowing that we’re really safe all together in the same place," Gillis said.

The Sony Pictures horror film, directed by Takashi Shimizu, has generated about $104 million at the North American box office, having cost less than $10 million to make. It is based on a Japanese film series, also directed by Shimuzu.

"The Grudge" DVD also includes a 55-minute five-part making-of documentary which includes 5-10 segments titled: "The Birth of The Grudge," "Myth of Ju-on," "Culture Shock: The American Cast in Japan," "Designing The Grudge House" and "A New Direction and Understanding Takashi Shimizu."