Box Office Preview: 'Gravity' Rocketing Toward $40 Million Debut

Adding intrigue to the weekend, Sony has decided to sneak "Captain Phillips" in 800 theaters Saturday night; modest prospects for Justin Timberlake-Ben Affleck gambling thriller "Runner Runner."

Alfonso Cuaron's 3D space epic Gravity is on the launchpad and ready to blast off into theaters at 10 p.m. Thursday in what's expected to bring a $40 million opening for Warner Bros., although the studio is predicting a more modest $35 million debut.

Either way, that's easily enough to win the weekend race in North America. The only other new wide player is New Regency and 20th Century Fox's gambling thriller Runner Runner, starring Justin Timberlake and Ben Affleck. Runner Runner is tracking to open in the $10 million to $12 million range, although the film saw gains across most demos in recent days.

STORY: 'Gravity' Premieres in New York, Sandra Bullock and George Clooney Hit Campaign Trail 

Adding intrigue to the weekend, Sony has decided to sneak Paul Greengrass' Somali pirate drama Captain Phillips, starring Tom Hanks, in 800 theaters on Saturday night a week ahead of its opening. Both Captain Phillips and Gravity are considered award contenders.

Starring Sandra Bullock and George Clooney, Gravity has generated enormous buzz after screening at all three of the marquee fall film festivals (Venice, Telluride and Toronto). The film cost roughly $100 million to produce.

Warners points out that October generally doesn't generate huge openings, particularly for adult-skewing dramas. David Fincher's The Social Network debuted to $22.4 million in October 2010, while Martin Scorsese's The Departed took in $26.9 million in early October 2006.

Gravity has several key advantages, however, including the upcharge for a 3D ticket. It also will play in Imax theaters, the favorite venue for fanboys. More importantly, it could skew younger than other fall adult dramas.

Gravity revolves around two astronauts left floating in space when their space shuttle is damaged (Bullock has a far bigger role). Producers include David Heyman, who played a key role in the Harry Potter franchise.

Bullock and Clooney aren't the only high-profile stars with movies opening on Oct. 4.

Costing roughly $30 million to produce, Runner Runner was directed by Brad Furman and also stars Gemma Arterton and Anthony Mackie. New Regency, which fully financed the film, partnered with Leonardo DiCaprio's Appian Way on the project.

The film, from a script by Brian Koppelman and David Levien (Rounders), revolves around a Princeton University student (Timberlake) who is lured into an Internet poker scam by the site's owner (Affleck).