NEW YORK - Ann Romney is guest-hosting "Good Morning America" next Wednesday.

ABC says the wife of Republican presidential hopeful Mitt Romney will be on hand at the morning news program for its 8 a.m. (Eastern time) hour. Joining George Stephanopoulos at the anchor desk, Mrs. Romney will be filling in for co-anchor Robin Roberts, who is on extended medical leave.

ABC says it is in discussions with first lady Michelle Obama for a similar guest appearance when her schedule allows.

Stephen Colbert, Oprah Winfrey and the cast of "Modern Family" have previously been announced to substitute for Roberts, who had a bone marrow transplant last month.

Roberts' absence came as "Good Morning America" has overtaken NBC's "Today" show in the ratings after years in second place.