Five months to the day after undergoing a bone marrow transplant, Robin Roberts on Wednesday made a heartwarming and inspiring return to the set of ABC's "Good Morning America."

"Hi, it's Robin, and I've been waiting 174 days to say this: Good morning, America!" declared a beaming Roberts, surrounded by her co-hosts. who greeted her with a hearty round of applause.

Roberts, 52, had been absent from the morning program since August, when she began to prepare for a bone marrow transplant to treat myelodysplastic syndrome (MDS), a rare blood disorder that can lead to a fast-growing form of leukemia.

"I keep pinching myself and I realized that this is real, this is actually happening," she said soon after the introduction of what ABC deemed a "very special edition" of "GMA."

Appearing thinner and rocking a close-cropped hairstyle, Roberts told viewers that "Faith, family and friends have brought me to this moment and I am so full of gratitude. ... I share this day of celebration with everyone."

Throughout the program, Roberts thanked those who aided her recovery, including her sister and donor, Sally-Ann. "Welcome Back Robin" video messages from luminaries, including President Barack Obama and his wife, Michelle, Hillary Clinton, Oprah and Magic Johnson, were also aired.

The president called Roberts "an inspiration to all of us" and added that "we couldn't be happier that you're back here doing what you're doing best."

ABC announced Roberts will interview the first lady later this week, to be shown next Tuesday.

A behind-the-scenes look at Roberts' journey will air on Friday's "20/20" (10 p.m., ABC).

Roberts' ordeal with MDS came just a few years after she was forced to battle breast cancer. And last August, just days before her bone marrow transplant, Roberts' mother died at the age of 88.