Bill O'Reilly is holding his tongue these days, thanks to a certain lawsuit factor.

The host of The O'Reilly Factor, Fox News Channel's number one show, clammed up on his lawyer's advice after being hit with a sensational sexual harassment suit last week by Andrea Mackris, an associate producer on the show.

Though O'Reilly appeared on Live with Regis and Kelly last Thursday to promote his new children's book, The O'Reilly Factor for Kids, he's scarcely been seen or heard from since.

He canceled appearances on ABC's The View, HBO's Real Time with Bill Maher, CBS' The Early Show and a Nov. 1 sit-down with PBS' Charlie Rose.

Last Friday, guest host Tony Snow took over helming duties in the "No Spin Zone," leaving Fox News with an O'Reilly-less Factor.

The garrulous gabber broke his silence briefly to explain his disappearing act.

"I have been advised to keep my big mouth shut, and I have promised to do that," O'Reilly explained to the New York Daily News on Friday.

"This has been the worst day of my life," he said. "I am getting hounded by the press, and I knew I would be. I knew that they were going to kill me, but what am I going to do?"

O'Reilly has hired a security detail to guard his Long Island estate and keep prying eyes away.

Meanwhile, Fox News has made the move to fire Mackris from her $93,000-a-year associate producer gig, but has reportedly asked a court to rule that the termination is not retribution for her lawsuit.

"We have asked the court to consider whether the allegations made public by Ms. Mackris are valid," Fox spokeswoman Irena Briganti told the Daily News. "We have also asked the court to advise Fox News about the possible termination of Ms. Mackris' employment. Ms. Mackris is still employed by and on the payroll of Fox News."

Mackris has not been allowed back in her Fox News office since filing her complaint.

The legal battle began last week after O'Reilly fired the first shot against Mackris, teaming with Fox to file suit against her and her attorney for allegedly trying to extort $60 million from him in exchange for filing the harassment suit.

Hours after O'Reilly filed his complaint, Mackris struck back with a lengthy court filing detailing lewd phone calls O'Reilly made to her against her will.

Both sides have since indicated in interviews that the suits were filed after settlement talks broke down.

Mackris' lawsuit (posted on The Smoking Gun) detailed raunchy phone calls she allegedly received from O'Reilly, in which he bragged about his "amazing" endowment, advised her to buy a vibrator and allegedly masturbated mid-conversation. Many believe Mackris recorded the conversations, given the graphic details provided in her complaint.

Mackris has said she repeatedly asked O'Reilly to cut out the inappropriate behavior, but Fox News has said that she never made any complaints about her work environment and even recently sent a friend an email gushing about her job.

Mackris alleged that O'Reilly intimidated her with threats of what would happen, should she come forward to accuse him of harassment.

Meanwhile, O'Reilly may have canceled promotional appearances for his children's book, but The O'Reilly Factor for Kids--which is subtitled A Survival Guide for America's Families and offers parents advice on talking to kids about everything from sex to bullying--is earning plenty of attention on Amazon.com.

"Which is more pathetic," one user posited about the book, "the fact that O'Reilly thinks he has anything useful to say about parenting, or the fact that some parents might earnestly believe he has something useful to say about parenting. To such parents, something useful to say would be: put your kids up for adoption, you losers!"

Another Amazon user seemingly took a more positive view of O'Reilly's tome.

"Oreilly [sic] is a good guy who has not been proved to done anything wrong he tried to do good by the kids guys out there who are jealous of the guy will say anything about him so you read some crap that he was accused of saying for christs sake I bet all the guys who put him down do the same thing the book is great so go teach your kids to go fight a war and then spit on your fellow soldiers you morons." (In case you didn't notice, we printed the review unedited.)

While O'Reilly seems to have retreated from the public eye for the time being, Mackris seems ready to hop in the ring.

During Mackris' first public interview last week, ABC's Bob Woodruff asked her if she knew what she was up against, pointing out that O'Reilly was "no shrinking violet."

"Neither am I," she replied.