NEW YORK (CNN/Money) - Domesticity diva Martha Stewart breached her fiduciary duty to investors when she allowed herself to be linked to the ImClone Systems insider trading scandal, an investor has alleged in a lawsuit.

Conrad Hahn, who owns shares of Martha Stewart Living Omnimedia Inc., sued Stewart last week in Manhattan state court. Hahn claims that Stewart, who is chairman and CEO of Martha Stewart Living, had a duty to investors to "maintain her good name and reputation and to avoid situations that could negatively impact her name and reputation," the lawsuit states.

The insider trading allegations against Stewart have caused shares of Martha Stewart Living Omnimedia to plunge nearly 60 percent. The stock fell almost 5 percent in Monday's trading to close at $8.12.

Hahn is asking that the lawsuit be certified as a class action representing all Martha Stewart Living shareholders as of Dec. 26. Hahn did not disclose how many shares he owns nor how much in damages he is seeking, according to court papers.

"The lawsuit is totally without merit and worthy of no further comment," said attorney Robert Morvillo, who is representing Stewart.

Stewart is currently being investigated as to whether she benefited from insider information when she sold nearly 4,000 shares of ImClone a day before the Food and Drug Administration rejected the biotech's cancer-drug application on Dec. 28. Stewart is a friend of ImClone's former CEO, Sam Waksal, who was arrested in June for trying to sell ImClone stock and tipping off family members to dump their stock after he learned of the FDA's decision.

Stewart has repeatedly defended herself, saying she had an existing verbal agreement with Peter Bacanovic, a Merrill Lynch stock broker, to sell her ImClone shares if the price dipped below $60. However, congressional investigators have yet to find any evidence of that pact.

Hahn alleges in the complaint that Stewart, a former Merrill Lynch stockbroker, knew or should have known that any improper conduct that she engages in will adversely affect Martha Stewart Living shares. On June 24, Martha Stewart Living Omnimedia admitted that the investigation into CEO Stewart has begun to hurt its business.

"Regardless of Stewart's criminal culpability for insider trading, by putting herself in a position that compromises her integrity and casts the specter of doubt on her public image or reputation, Stewart has breached her fiduciary duty to MSO shareholders," Hahn said in the complaint.