Herman Cain insisted on Tuesday that he didn't know Sharon Bialek, rejecting her claim that he groped her and made an unwanted advance after they had dinner in Washington, D.C., in 1997. "I reject all that. I don't remember it. And also, I don't remember knowing her," the Republican candidate told ABC News's Jonathan Karl.

Bialek, a former Chicago-based fundraiser for the National Restaurant Association's Education Foundation, has accused the upstart candidate of putting a hand up her skirt and trying to force her head toward his crotch when she met with him in 1997 to ask for help finding a job. Cain was then the president of the association.

"We've got about 150 employees in the washington office and about 150 employees in the chicago office," Cain added in the ABC interview. "I didn't have interaction with all those employees on a regular basis. I sat there trying to recall who she was and if I knew her. And I am honestly telling you I don't even recall knowing her back then."

Cain is scheduled to hold a press conference this evening to discuss Bialek's charges further. He had already gone on the offensive Tuesday with an email-blast statement attacking her personal history.

He told ABC's Karl that he considered Bialek's claim a "vicious, baseless attack on my character and my integrity."