The wife of Republican presidential hopeful Mitt Romney will be on hand at the morning news program for its 8 a.m. hour.
Mrs. Romney will be filling in for co-anchor Robin Roberts, who is on extended medical leave. Previous guest hosts include Stephen Colbert and Jessica Simpson.
ABC said it is in discussions with first lady Michelle Obama for a similar guest appearance.
Roberts underwent a bone marrow transplant to treat MDS, a blood and bone marrow disease, on Sept. 20. During the procedure, she was surrounded by sisters Sally-Ann and Dorothy, and other loved ones including "World News" anchor Diane Sawyer and "GMA" weather anchor, Sam Champion.
It is not yet known when Roberts will return to the morning show.
The Associated Press contributed to this report.