NEW YORK (CNN/Money) - Embattled lifestyle guru and media executive Martha Stewart has hired a high-profile defense attorney to join her already top-flight legal team.

Stewart has hired Robert Morvillo, of Morvillo Abramowitz Grand Iason & Silberberg, a spokeswoman for the law firm confirmed. Morvillo helped defend brokerage firm Merrill Lynch & Co. when it faced charges brought by New York Attorney General Eliot Spitzer related to its analysts' recommendations.

Morvillo joins Wachtell Lipton Rosen & Katz in New York and Arnold & Porter in Washington, D.C., as part of Stewart's defense team.

Stewart is facing questions on whether she had insider information when she sold nearly 4,000 shares of ImClone Systems Inc. stock last December the day before it was revealed that the Food and Drug Administration was refusing to consider the application for its key cancer fighting drug. Stewart has denied any wrongdoing in the case.

On Tuesday, the home style guru bowed out of her weekly Wednesday appearance on CBS's "The Early Show" because of the ImClone scandal. Last week, the host of the CBS show pressed Stewart for information on the ImClone situation.

The media executive's company, Martha Stewart Living Omnimedia Inc., also hired public relations firm Brunswick Group this week, a Brunswick spokesman said. The Susan Magrino Agency will continue to represent Martha Stewart.

Martha Stewart, left, and CBS's "The Early Show" co-host Jane Clayson.

While Stewart maintains her innocence and has yet to be charged with any wrongdoing, her sale of the stock is being examined by the Justice Department for possible criminal charges, by the Securities and Exchange Commission for possible securities violations, and by congressional investigators. Former ImClone CEO Sam Waksal, a friend of Stewart, is facing federal criminal charges for allegedly violating securities laws.

Shares of ImClone (IMCL: Research, Estimates) dropped nearly three percent Wednesday in afternoon trading.

Separately, Waksal refused to testify 223 times during a private June 27 deposition. The former ImClone CEO, testifying in a civil lawsuit against Scientia Health Group, which was formed by Waksal and other investors in late 2000, invoked his Fifth Amendment right against self-incrimination to a variety of questions, attorney Joseph Lee Matalon confirmed.

Matalon is representing James Neal, the former president of Scientia, who claims he was fired after confronting Waksal about illegal actions at Scientia.

Waksal was arrested last month and charged with securities fraud, conspiracy and perjury. The former ImClone CEO allegedly tipped off two family members about the Food and Drug Administration's refusal to consider ImClone's application for the drug cancer-fighting drug Erbitux before the news officially became public last December. In June, Waksal declined to testify before a congressional panel probing the Erbitux rejection.

New York-based Scientia, an investment fund created to acquire other health-care companies, raised $40 million in November from major investors such as Wall Street titans Carl Icahn and Leon Black, Matalon said. Waksal served as executive chairman of Scientia.

During the deposition, Waksal declined to answer whether he was co-mingling his own personal funds with Scientia's.

"Waksal invoked the Fifth Amendment as to virtually all questions about Scientia," Matalon said. "Even the most innocuous questions such as whether he had health benefits from the company or even heard of [it]."

Waksal's attorneys advised the former ImClone CEO to invoke the Fifth Amendment because he had already invoked his right to silence before Congress last month, spokesman Scott Tagliarino said.

Scientia could not be reached for comment.