ABC's Robin Roberts has received floods of messages from fans and friends after announcing her blood and bone marrow disorder this week.

Five years after battling breast cancer, Roberts, 51, announced Monday she would begin chemotherapy for myelodysplastic syndrome. Also known as MDS, the disease affects blood and bone marrow and was once referred to as pre-leukemia.

The "Good Morning America" co-host also revealed that she would receive a bone marrow transplant from her older sister, Sally Ann Roberts, sometime this fall.

Immediately following Roberts' announcement, messages of support and prayers flooded social media sites from both fellow celebrities and loyal viewers of "GMA." In response to the outpouring of messages Roberts gratefully thanked everyone, noting how much the messages have helped her.

"I slept like a baby last night for the first night since my diagnosis," she said at the top of "GMA" Tuesday morning. "My family and I are overwhelmed and comforted by the response from everyone."

Among the dozens of celebrities and leaders who sounded off on social media sites, Michelle Obama also wished the co-host the best.

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