Lindsay Lohan 'in a tailspin,' had to be forced to do movie scene with Charlie Sheen, report says

Getting unpredictableLindsay Lohanto do a cameo role in Scary Movie 5 has been a frightening experience for producers, as she tried to avoid a scene making fun of her troubles, The Post reports.

Dimension Films signed Lohan to play a cameo in the horror spoof oppositeCharlie Sheen. But over the past two weeks as the date for filming approached Lohan disappeared, blew off rehearsals, missed her flight to the set and even bizarrely claimed she had walking pneumonia.

The Post reports the troubled starlet freaked out after seeing the script was poking fun at her. At the 11th hour, Lohan did report for work, however only after she was threatened with a lawsuit by a Hollywood legal eagle and a private jet was sent to pick her up, sources tell The Post's Page Six.

Lindsay missed every meeting she had for the film, including script reads and wardrobe meetings, said a Hollywood insider. Then she missed her flight to Atlanta on Sunday to shoot the movie. The producers had been getting signs Friday that she was a mess, and would not be fit to work.

Another summed up, Shes been locked up in her room at the Bowery Hotel. Shes been in a tailspin. Even Charlie Sheen worried she might not be able to do the scene.

A rep for Lohan told The Post: These stories are untrue, and she is willingly fulfilling all of her obligations. Reps for Dimension had no comment.

Go to The Post for more on Lohan's walking pneumonia claim.