Credit: Valerie Macon/Getty Images

Jillian Michaels, who has appeared on NBC's The Biggest Loser and Losing It with Jillian, is firing back at the Los Angeles Times, which printed a scathing op-ed piece this week, calling her "an actress playing the role of fitness trainer."

Among the allegations in the piece (written by James S. Fell, a certified health expert based in Canada): Michaels' techniques are shoddy and her routines unsafe.

Asked about the claims Wednesday at a Guess/Marie Claire event, Michaels scoffed. "Apparently I'm an actress," Michaels, 36, sarcastically told "Shame on the Los Angeles Times for saying I'm a fraud and not a trainer. I currently own two certifications, one of which doesn't expire. I developed my own continuing education program for trainers, with sports medicine doctors. I've been a trainer since I was 17-years old for 19 years."

She told Us she plans to take legal action.

Said Michaels, "I'm going after them."

While chatting with Us, actress Vanessa Marcil overheard the conversation and asked if the op-ed piece was really that bad.

"Honey, they said I was a total fraud!" Michaels responded. "They didn't do any of their homework. They flat-out [lied]. It's defamation, it's libel, it's full-on."

In recent months, Michaels has been slammed with law suits over her dietary supplements.

In August, an anonymous plaintiff filed a $10 million suit alleging that her product, "Triple Process Total Body Detox & Cleanse," contained dangerous ingredients.

Last February, two women separately sued Michaels for false advertising on a diet pill she endorses, "Jillian Michaels Maximum Strength Calorie Control."

Michaels has said the suits are "baseless" and is standing by the supplement and its Utah-based maker, ThinCare International. "My reputation and credibility are of the utmost importance to me," she told the Associated Press.