The Clintons are planning a week of appearances with some of the highest-rated talk show hosts in the country, including Oprah Winfrey, who has already announced her support for Senator Obama in the 2008 presidential race.

Senator Clinton kicked off the TV barnstorm last night with her seventh appearance on the “Late Show with David Letterman,” a regular stopover for presidential contenders.

On Tuesday, Mrs. Clinton will join comedian turned daytime host Ellen DeGeneres for her show’s season premiere. Ms. DeGeneres has an almost entirely female audience that could be a crucial demographic for Mrs. Clinton if she secures the Democratic nomination and makes it to the general election.

The talk-show circuit has already given the 2008 presidential contenders some serious face time with potential voters. Mr. Obama, John Edwards, Senator McCain of Arizona, and Senator Biden of Delaware have all made recent appearances on Comedy Central’s “Daily Show With Jon Stewart,” which has become a something of a prerequisite for candidates trying to appeal to the show’s politically savvy generation of viewers. During the upcoming Clinton talk show blitz, it is President Clinton’s Tuesday appearance with Ms. Winfrey that has the greatest potential to yield a unique — and possibly awkward — television exchange.

Ms. Winfrey has already declared her support for Mr. Obama, Mrs. Clinton’s most formidable Democratic rival. The endorsement of the Illinois senator is the first Ms. Winfrey, whose influence with her audience has created best-selling books overnight, has made in a presidential race. And she is not just endorsing him — she is set to hold a huge fund-raiser at her home in Santa Barbara, Calif., for Mr. Obama in California on September 8.

Just hours after his “Oprah” appearance, Mr. Clinton, who will be talking about his new book on charitable giving, will hit CNN’s “Larry King Live.” His final appearance will be on the “Late Show” on Wednesday night.