A certifiable Web ruckus is erupting over an image that surfaced this week of Tom Cruise on the set of "Tropic Thunder." Just a few weeks after star/director Ben Stiller carefully evaded MTV News' questions about the top-secret comedy cameo, reps are reportedly having the image of a fat, balding Cruise pulled from the Internet as quickly as sites can put it up.

Next July, the proof will be in the pudding, as Cruise has apparently gone James Lipton for a role as a studio head. In the meantime, however, "Thunder" star Jack Black is among those disappointed by the party-crashing long-lens camera shot that appeared on gossip sites such as JustJared.com.

"People are saying they've seen this," shrugged Black during an interview for his new film, "Margot at the Wedding." "That's not supposed to happen."

Described as a funny "Apocalypse Now," the movie stars Black, Stiller, Robert Downey Jr. and Matthew McConaughey in the tale of in-over-their-heads actors caught up in a real-life action story.

"That's what this hairdo is all about," Black said, pointing to his newly blond locks. "My character is kind of a Chris Farley-type actor. It's a movie within a movie. All these actors are going to make a Vietnam War film, and once we get there, we fall into a bad trap. We go into the jungle, and we trespass by accident into the drug warlords' territory. We're in real danger, but we think it's all part of the movie and we just keep acting."

Cruise doesn't need to do any acting, however, to show his displeasure over the apparent leak. According to several news outlets, the "Lions for Lambs" actor is considering legal action, and his representatives have issued a statement reading: "Mr. Cruise's appearance was supposed to be a surprise for his fans worldwide. ... [Paparazzi] have ruined what should have been a fun discovery for moviegoers."

Black said he hadn't yet seen the shot. "I can't believe it got leaked out," he said. "Could you tell it was him?"

Informed that Cruise's face is still quite visible through the heavy makeup, Black let out a sigh and finally admitted what Stiller would not. "Yeah, he's going to be very funny in this movie," Black said of Cruise. "It was supposed to be a secret, but there it is."

Check out everything we've got on "Tropic Thunder" and "Margot at the Wedding."

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