Jeremy Piven has finally addressed the rumors about his recent mercury poisoning, after unexpectedly dropping out from a play he was working on.

Piven was in the middle of his well-reviewed run of the David Mamet Hollywood-themed play when he abruptly dropped out and blamed it largely on sushi.

The Entrouge star appeared on Good Morning America on Thursday to discuss why he left the play, Speed-the-Plow.

The last thing I ever thought about doing was not completing this run, Piven explained to host Diane Sawyer. I've never not completed anything in my life. They pulled me out of this thing, and that's the truth.

He added, I was living my dream. We had brilliant reviews. We were sold out every night. This was the greatest time of my life. I would have loved to go out. I couldn't do it.

The jokes on his behalf began when his playwright, David Mamet, joked that he was leaving show business to pursue a career as a thermometer.

The only protein I got for 20 years was from fish, says Piven, who adds that he ate sushi at least twice a day. I kind of thought I was doing the right thing ... As soon as I heard this, I stopped all fish whatsoever.

But Piven, who hasn't eaten fish in five months, says he has no hard feelings: [Mamet] is a brilliant playwright and that's a funny line.

Dr. Carlon Colker, who is treating Piven, detailed his condition to ABC News saying, This is a situation of mercury toxicity. His level [of mercury] was quite high, almost six times the normal limit… In this case, it's either because of fish - he ate sushi twice a day for years - or because of the Chinese herbs he was taking, or both. We're pretty sure about the fish. How much the Chinese herbs contributed, we don't know. We don't have the specifics of which herbs he took.

He'll be OK, Dr. Colker adds. I think it'll take a few weeks to a couple of months. Unfortunately it was like pulling teeth to get him out of the show. This is a situation that I think will resolve as long as he's attending to his health.