Hollywood stars who behave badly usually can rely on politely coded coverups (hangovers are "the flu," blood feuds are "creative differences"), but when problems surfaced on the set of "Georgia Rule," a furious executive gave it to Lindsay Lohan with both barrels in a letter sent this week.

Telling the 20-year-old starlet that she has "acted like a spoiled child," James G. Robinson, the chief of Morgan Creek Productions, wrote in the letter that he sees through Lohan's alibis of illness and fatigue, which have hampered the filming of the Morgan Creek project.

"You and your representatives have told us that your various late arrivals and absences from the set have been the result of illness; today we were told it was 'heat exhaustion.' We are well aware that your ongoing all night heavy partying is the real reason for your so-called 'exhaustion,' " Robinson wrote in the letter that was posted Friday on the Smoking Gun website.

The letter, authenticated by a spokesman for Morgan Creek, is dated Wednesday and addressed directly to Lohan at the Chateau Marmont. Also on Wednesday, Lohan's publicist, Leslie Sloan Zelnick, told "The Insider" television show that her client had been taken a day earlier to a local hospital to be treated for dehydration and overheating. Zelnick didn't return phone or e-mail requests for comment.

"Georgia Rule" is being filmed at Sunset Gower Studios and also stars Jane Fonda and Felicity Huffman. In it, Lohan plays a rambunctious, troubled teen who is dragged by her mother (Huffman) to spend a summer with her grandmother (Fonda). In his letter, Robinson told Lohan she has "alienated many of your co-workers and endangered the quality of this picture" and that "your actions have resulted in hundreds of thousands of dollars in damage."

Robinson, 70, is known for his strong and maverick personality ("He's as subtle as an anvil," one admirer said with a chuckle on Friday), and Hollywood insiders said the scolding tone and the fact that the letter was addressed directly — it starts off "Dear Lindsay," as opposed to an agent or other intermediary — was in keeping with the exec's brand of business. Others noted that it might be the first shot in a legal war, which could also explain its covert dissemination.

Greg Mielcarz, a spokesman for Morgan Creek, confirmed that the letter is genuine and said he believes that the Smoking Gun has a copy on letterhead, not a facsimile. The letter has six names on the bottom of people who received it, including agents, producers and others involved in the project. Regardless of its origin, the letter was greeted with groans, giggles and fascination in Hollywood, where Lohan has become as notorious for her tabloid life as for her filmography. The star's weight, claims about her nightlife and brashness have made her an irresistible figure to the gossip-minded. On her last three films, Lohan has missed time on the set and each time cited health ailments and medical care as the reason.

Lisa Stewart, co-producer of the 2005 Lohan vehicle "Herbie: Fully Loaded," declined Friday to discuss the letter or the type of behavior it describes ("I'm not as bold as James Robinson," she said), but she did say that Lohan is costing herself career opportunities with her current talent for trouble.

"She's got a lot of talent, and it's being overshadowed by her reputation, and it's a shame," Stewart said. "Right now Lindsay can't seem to stay out of the press. She has ability as an actor; the camera loves her."

The main topic in Hollywood circles on Friday though was the delicious candor of the letter. It also cuts against the edict that studio execs shouldn't bad-mouth talent in public for reasons of project preservation and the ever-changing winds of personal fortunes.

"It's a letter that has people saying, 'Finally, someone is saying what they think and not letting some young star dictate what is acceptable,' " said one New York-based publicist who works with film stars. Another called it "a wake-up call" for Lohan and a signal that she has "run out of polite lies and chances to act like a grown-up."

Perhaps, but those insiders also spoke on condition of anonymity, suggesting that Lohan is not washed-up enough that they would risk her ire. One publicist who did speak on the record was Dale Olson, whose long career included work for Rock Hudson, Steve McQueen and Gene Kelly. He said celebrity has completely trumped craft in the current era.

"He is slapping her hands, and I found it refreshing that he was direct and didn't go through an agent," Olson said. "It's impossible really to have a secret in this town these days, but still, many people will never say what they think or be honest about what's going on. Many of the young stars today don't take their craft seriously — if it is craft — and they make too much money and don't know how to behave."