Good Morning America co-host Robin Roberts will begin her medical leave at the end of the week.
Roberts announced during Monday's show Friday will be her last day before beginning the process for a bone marrow transplant.
The 51-year-old previously announced on air that she is battling myelodysplastic syndrome, a rare blood disorder, five years after completing treatment for breast cancer.
ABC's Diane Sawyer and Barbara Walters are among the hosts scheduled to fill in for Roberts.
It is unclear when Roberts will return to the morning show.
- July 27, 2012: Robin Roberts to take medical leave from Good Morning America
- June 11, 2012: ABC's Robin Roberts has blood, bone marrow disorder