ABC's Robin Roberts home from hospital

NEW YORK (AP) — ABC's Robin Roberts has come home from the hospital three weeks after undergoing a bone marrow transplant.

After thanking her doctors and nurses and singing "Amen," the "Good Morning America" host began the next stage of recovery from MDS, a blood and bone marrow disease. Her sister was the donor for her bone marrow.

While leaving the hospital after a month is a big first step. Roberts' doctor explained that it still will take time for the patient to gather strength and build up her immune system.

"Good Morning America," now the top-rated network morning show, aired a story about Wednesday's homecoming. The show has brought in occasional celebrity guest hosts such as Stephen Colbert to fill in for Roberts.