Robin Roberts
"Good Morning America" co-anchor Robin Roberts is a breast cancer survivor,. She has also fought a rare blood disorder known as myelodysplastic syndrome. Wikipedia

Good Morning America host Robin Roberts has announced that she will be taking a medical leave from the ABC show.

During the leave, which will become effective in late August or early September Roberts will undergo a bone marrow transplant, the GMA anchor said in a satellite interview with reporters at the Television Critics Association media tour.

Roberts, 51, revealed to the public earlier this year that she had been diagnosed with a blood disorder called myelodysplastic syndrome (MDS), which was likely caused by her treatment for breast cancer five years ago.

"Sometimes treatment for cancer can lead to other serious medical issues, and that's what I'm facing right now," she said on GMA in June.

In the months following the announcement, Roberts reportedly underwent chemotherapy as preparation for the transplant

During her absence, various substitutes, including Diane Sawyer, Katie Couric, Barbara Walters and Kelly Ripa, will reportedly fill in for Roberts, the Associated Press reports.

Roberts joined ESPN as a sportscaster in February 1990 and became well known on "Sportscenter" for her catchphrase, "Go on with your bad self!" She began to work for ABC News, specifically as a featured reporter, for "Good Morning America" in June 1995.