Jeremy Piven is actually very sick, his doctor insisted on revealing amid reports the "Entourage" star ditched David Mamet's Hollywood play "Speed-the-Plow."

Even though you probably never heard of any medical condition caused by "shockingly high" levels of mercury, the abnormality causes extreme fatigue, impairment of vision, speech and hearing, severe lethargy, lack of coordination, and is dangerous for one's health, including Jeremy Piven's who was forced to drop out of the Broadway production despite his critically acclaimed performance. 

Those associated with the show are keeping tight-lipped regarding the Emmy-award winning actor’s impromptu departure, but his doctor Carlon Colker took all the blame telling People magazine he "pulled Jeremy from the show" because he was suffering from elevated levels of mercury. 

The 43-year-old actor told producers earlier this week that he hadn't been feeling well due to a "high mercury count," prompting a series of skeptic remarks from playwright David Mamet who mockingly told the press that Piven "would be leaving the show business to pursue a career as a thermometer."

However, according to Dr. Carlon Colker, who is an internist and attending physician at Beth Israel Medical Center in New York City and Greenwich Hospital in Connecticut, the decision is based on medical results, and Piven, one of the most hardworking people in the business, initially opposed it and did his best to fight the symptoms.

"He's disappointed that I had to pull the plug," Colker told People. "But I think he's hurt more by the comments that he's not trying or that he walked away. He's been working straight for 30 years. He doesn't walk away; I tore him away from it."

Apparently, all that mercury in his system might be due to Piven's diet, which is rich in fish. Piven, who regularly eats sushi twice a day for years, has also taken certain Chinese herbs that, along with the sushi, could have led to elevated mercury levels.
The first symptoms manifested back in October when Piven reportedly told the show's producers that he was worried he might be suffering from mononucleosis (the kissing disease) and the Epstein-Barr virus.

Last week, Piven's condition got more serious, he began experiencing neuro-muscular dysfunction, which led to extreme difficulty in lifting his arms and legs, and on Sunday, he felt dizzy. He was forced to miss Tuesday evening’s performance and skip the show’s two Wednesday perfs. 

Piven underwent a series of tests which failed to identify his condition but when Colker checked his "heavy metals," he was "absolutely stunned" to find mercury at a level "almost six times the upper limit of normal and allowable."

Mercury can be fatal; it can cause cardiac arrest, kidney failure and even psychiatric problems. However, Piven was ordered to cut back on his fish and Chinese herbs consumption and he will be fully recovered by March. 

The actor's publicist said Piven would have liked to continue his role his role as Hollywood producer Bobby Gould in "Speed-the-Plow" but he had to follow his doctor's advice and end his run immediately.

Producers of the play said on Thursday that Emmy winner William H. Macy, who has a long association with Mamet, and Tony award winner Norbert Leo Butz, will take over the role of the foul-mouthed studio executive. Butz is to play the role from Tuesday through Jan. 11, the producers said, and Macy will take over from Jan. 13 through Feb. 22, when the show is scheduled to close at the Ethel Barrymore Theater.