The nephew of Democratic U.S. Sen. Edward Kennedy of Massachusetts said in a statement that the allegations are false, calling them "outrageous, untrue and without merit." The statement from the Center for International Rehabilitation, which Kennedy Smith leads, said the woman had demanded $3 million.
"Unfortunately, my family and my personal history have made me unusually vulnerable to these kinds of allegations," Smith said in the statement.
In 1991, a jury in West Palm Beach, Fla., acquitted Kennedy Smith, now 43, of sexual assault and battery on a then 30-year-old woman.
The new accusation is made in a lawsuit filed Wednesday in Chicago. In the civil suit, 28-year-old Audra Soulias alleges that after a night of drinking, Kennedy Smith forced her out of a cab and into his Chicago home where he sexually assaulted her. She is seeking more than $50,000 in damages.
"He dragged me into his house, dragged me upstairs in his bedroom where he raped me," Soulias told CBS News Station WBBM-TV in Chicago.
Soulias alleges that after the January 1999 assault, Kennedy Smith left her voicemail messages apologizing for his behavior.
Soulias and her attorney are expected to comment on the case at a news conference Thursday afternoon.
Private investigator Paul Ciolino told the Chicago Sun-Times that he gave Soulias a polygraph test, which she passed.
A jury in 1991 took about an hour to acquit Kennedy Smith of second-degree sexual battery and misdemeanor battery charges brought by a woman who alleged that he raped her at his family's estate in Palm Beach, Fla, after they met at a nightclub. He testified that the sex was consensual.
William Kennedy Smith is one of four children of former Ambassador to Ireland Jean Kennedy Smith, who is the second youngest of nine siblings including President John F. Kennedy and Sen. Robert F. Kennedy - who were both assassinated - and Sen. Edward Kennedy.
Like many of the Kennedy clan, William Kennedy Smith has been involved in public service and was the founder of Physicians Against Landmines, a group that later became part of the Center for International Rehabilitation.
Smith remains active as chairman of the group, which works with Northwestern University and the Rehabilitation Institute of Chicago to help the disabled in the world's poorest countries.
At least three other Kennedy relatives are on the board of directors: Smith's mother, Jean Kennedy Smith; Carole Radziwill, a TV producer; and Edward M. Kennedy Jr., an attorney and advocate for the disabled who lost a leg to cancer as a child.
Coincidentally, Wednesday was a big day for Smith's group, as a report it co-authored with several other advocacy groups was presented to a United Nations committee which is drafting an international treaty to protect the rights of the world's 600 million disabled.