Here's an ideal topic for Oprah Winfrey's talk show: When good actors make bad movies. And you couldn't find a more ideal panel than the cast of the boring science-fiction/thriller "Deep Impact."

Over the past 10 years, there have been what seems like hundreds of disaster movies. But very few of them have felt as uninspired and dull as this one, which is so plot and dialogue heavy that it recalls the worst efforts of Irwin Allen ("The Towering Inferno," "The Swarm").Of course, you couldn't possibly blame this dud on the actors, who include Robert Duvall, Morgan Free-man and Vanessa Redgrave, or say they didn't try (you could question their choice of movie projects, however). But let's face it, the "killer comet" thing has already been done to death - and just think, there's already another movie like it, "Armageddon," waiting in the wings.

Tea Leoni stars as Jenny Lerner, a young newswoman who accidentally stumbles on the story of the century. Investigating what she believes is a presidential sex scandal, she discovers that Earth is threatened by an "extinction-level event" - a massive comet that's on a direct collision course.

Suddenly forced to show his hand, President Tom Beck (Freeman) discloses that the U.S. and Russian governments have approved a risky space mission, sending a team of astronauts (including Duvall and Ron Eldard) into space with nuclear warheads to either destroy the comet or at least divert its path. However, the effort fails, and the comet splits into two and is still on track to smack the planet.

While the astronauts desperately try to catch up with and destroy the larger section of the comet, the president also reveals the existence of a massive limestone cave - a so-called "ark," with room for only 1 million Americans Americans, who will be chosen by a special lottery.

To its credit, "Deep Impact" does pose one pretty interesting question: What would you do if you thought you had just weeks to live? Unfortunately, the film seems to take that long to answer it.

Bruce Joel Rubin's script is filled with too many characters and subplots, none of which get enough time to affect us in any way, and most of the special effects action doesn't come until the last 10 minutes of the movie.

And director Mimi Leder ("The Peacemaker") lets the dramatic scenes linger on way too long, undercutting the stars' mostly solid performances (though Leoni sabotages her scenes with her monotone mumble).

"Deep Impact" is rated PG-13 for profanity, violent mayhem and some vulgar references.