Five former first ladies are expected to attend a celebration Friday for the 20th anniversary of the Betty Ford Center for drug and alcohol abuse.
"People have told us that this many first ladies getting together is extraordinary. It speaks to their respect of Mrs. Ford," center President John Schwarzlose said.
President Bush and First Lady Laura Bush will send videotaped remarks, he said.
Tickets cost $1,000 for the private event, which will be closed to the news media. CNN's Larry King is master of ceremonies, with baritone Josh Groban as the featured performer.
Ford's candor about her drug dependence is largely credited with helping break the silence for many alcoholics and drug addicts.