Hollywood star Jeremy Piven is urging television viewers to eat fish with caution and have their mercury levels checked before they become crippled by its horrible effects. Piven was ordered by his doctors to pull out of the Broadway play "Speed-The-Plow" last month because his mercury levels were "shockingly high." Speculation began to surge when the "Entourage" star blamed his rare illness on eating too much sushi, with the plays author, David Mamet, remarking, "My understanding is that he is leaving show business to pursue a career as a thermometer." But Piven appeared on "Good Morning America" today and urging viewers to reel in their love of fish. He says, "The last thing I ever thought about doing was not completing this run. I've never not completed anything in my life. I'm very proud to say that I've been a workhorse my entire life. ... they pulled me out of this thing and that's the truth. "I come from a theater family -- you talk about the show must go on -- this is in my DNA. This was my finest moment -- that I had been working for my whole life." He also said, "Get your heavy metals tested, please, I beg you. Guys, go to bluevoice.org. You'll learn more information about all of this. It's much bigger than me. We're polluting our food source and it's not a great thing that's going on. Thank you."