Elisabeth Moss appeared on Bravo's Plead the Fight and dissed Jeremy Piven.

Elisabeth Moss appeared on Bravo’s ‘Plead the Fifth’ and dissed Jeremy Piven.

Elisabeth Moss, who now stars on the hit show “Mad Men,” still harbors ill will toward Jeremy “Sushi Boy” Piven, over his sudden departure from the Broadway show Speed the Plow nearly five years ago. In a recent interview she called him “highly unprofessional.”

In 2008, Piven bowed out of his starring role in David Mamet’s acclaimed play, insisting he was suffering from fatigue due to mercury poisoning.

The culprit — eating too much raw fish and supposed Chinese herbal supplements laced with poisonous mercury. Or so claimed his “feel-good” celebrity doctor Carlon Colker, who has a shady past.

Among other things, Colker had a run-in with the Federal Trade Commission over bogus claims he made about a love potion that he’d concocted and hawked in television infomercials.

Moss, 30, played Karen while Piven played Bobby Gould. Raúl Esparza starred as Charlie Fox in Mamet’s satirical deconstruction of Hollywood.

Host Andy Cohen brought up Piven on Bravo show “Plead The Fifth” which tries to elicit candid answers from celebrities. After asking about Mad Men co-star Jon Hamm’s “ham” (she dodged that one) he popped the Piven question.

‘What besides eating too much sushi caused Jeremy Piven to leave Speed-The-Plow?” he asked.

“That’s a good one, that’s a very good one, I could go on and on,” she said. “It came out of nowhere. He just didn’t come back one day.”

Piven, who ducked out of the show two months before the end of its run, drew widespread scorn The play’s producers filed an arbitration claim against him. But William H. Macy stepped into the part and the show recouped its $2.26 million production cost.

The arbitration panel ruled in 2009 that Piven did not break his contract.

At the same time, The National Fisheries Institute, which represents the seafood industry, issued a stern statement saying “no peer reviewed medical journal has ever published any evidence of a case of methylmercury poisoning caused by the normal consumption of commercial seafood in the U.S.”

Check out Moss’s reaction below and follow TheImproper on Twitter for more theater updates.