Walt Disney is turning to baseball to hype a 3-D movie about secret-agent guinea pigs.

Walt Disney Pictures has signed a deal with Major League Baseball for undisclosed terms under which the entertainment giant will give away 1 million tickets to the movie “G-Force,” scheduled to open nationwide on July 24, if a grand slam home run is hit at the sport’s All-Star game on July 14.

“G-Force” is a comedy adventure about a covert government program in which guinea pigs are trained to work in espionage. “Armed with the latest high-tech spy equipment, these highly trained guinea pigs discover the fate of the world is in their paws,” says Disney.

Under the program, a grand slam at baseball’s mid-summer classic means a free ticket for the first million people to register at Disney.com between April 22 and July 14, as well as the more than 46,000 fans attending the game in St. Louis.

If no grand slam is hit, no free tickets. In 79 previous MLB All-Star games, the only grand slam was hit in 1983. (Thank you, Fred Lynn).

Most U.S. sports have been hurt by consumer and corporate spending cutbacks in the recession. Major League Baseball officials expect attendance to fall as much as 10 percent this season, but that still translates to more than 70 million people at the games. And companies are still drawn to the sport as recent marketing deals have shown.

The last movie to use the MLB All-Star game to promote its debut was Disney’s “Angels in the Outfield” in 1994.

“G-Force” also will be part of the All-Star voting, appearing on more than 20 million ballots distributed at the 30 MLB ballparks, more than 100 minor league parks, and through in-stadium messages and announcements.

The Jerry Bruckheimer-produced movie stars the voices of Sam Rockwell, Tracy Morgan, Penelope Cruz, Nicolas Cage, Jon Favreau and Steve Buscemi.

Hey, it may be guinea pigs, but check out Bruckheimer’s track record. His credits include such hits as “Flashdance,” “Beverly Hills Cop,” “Top Gun” and “Pirates of the Caribbean” in theaters, as well as “CSI” and “The Amazing Race” on TV.

Baseball is careful about how it ties into movies, however.

You will see no “G-Force” logos on any bases. In 2004, baseball officials scrapped plans to promote the “Spider-Man 2″ movie on its bases after a major public outcry.

(Photo courtesy of Disney.go.com)