Lindsay Lohan chided in leaked studio letter

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.