Robin Roberts diagnosed with blood disorder

"Good Morning America" anchor Robin Roberts revealed yesterday that she has been diagnosed with myelodysplastic syndrome, a blood disorder.

The 51-year-old ABC News reporter beat breast cancer five years ago and told viewers her cancer treatment triggered her current blood disorder.

Roberts was upbeat when making the announcement live during yesterday's show and said she will begin chemotherapy to prepare her for a fall bone marrow transplant.

"My doctors tell me I'm going to beat this -- and I know it's true," she said in the statement.

ABC's medical correspondent, Dr. Richard Besser, said in a statement that he was consulting with Roberts about MDS, a rare malignant bone marrow disorder.

Roberts will continue hosting "GMA" but is expected to stay off the air for several months after the transplant to recover.