LOS ANGELES (Reuters) - Ann Romney, wife of Republican presidential contender Mitt Romney, will co-host top U.S. breakfast TV show "Good Morning America" for one day next week, ABC News said on Thursday.

Mrs. Romney, who will be guest co-host for an hour on October 10, is one of a number of celebrities to join George Stephanopoulos at the anchor desk while Robin Roberts is on medical leave.

GMA producers said they were also in talks with First Lady Michelle Obama, but are still trying to find a suitable time.

Ann Romney and Michelle Obama have made frequent appearances on TV chat shows as the 2012 presidential election campaign nears its climax in November.

Mrs. Romney made her first late-night TV stop last month on Jay Leno's "The Tonight Show", while Mrs. Obama has made regular appearances on popular shows such as "The View," "The Ellen DeGeneres Show" and the "Late Show With David Letterman."

ABC's "Good Morning America" has an audience of about five million and recently unseated NBC's "Today" as the most-watched of the three leading U.S. breakfast shows.