Robin Roberts calls in to Oprah on 'GMA'

• First live chat with 'GMA' anchor
• Oprah co-hosts the show for an hour
• Would be 'easier' not to be so public, says Roberts

Was that a tear streaming down Oprah Winfrey's cheek? It looked like it this morning — right after a rousing rendition of Ain't No Mountain High Enough from the Power in Praise choir, and just before Robin Roberts called in to Good Morning America.

The GMA anchor phoned in to her ABC show in her first live chat since her bone marrow transplant.

"I'm standing in for you, Robin!" shouted Oprah, who co-hosted the 8 a.m. hour.

"Usually I'm watching in between my toes in bed. You got me on my feet. You got me dancing this morning," said Roberts, who could be heard but not seen. "It's all about being uplifted."

When Oprah asked her how she's doing, Roberts replied, "It's Day 35. Thirty-five days ago I had my bone marrow transplant. It is a journey, my friend, as you have taught me."

Roberts, 51, went on to say, "I am so incredibly blessed to be doing as well as I am. Some days I do feel like I am 35 days old and can't get my head off the pillow. But those days are becoming fewer and fewer."

She told her cohorts at GMA and Oprah, "I can't wait to come back! ... It's just about understanding the moment. Why I'm here now. I'm journaling. You'd be very proud of me, Oprah. Journaling a lot. And just so appreciative of the outpouring. Not just for me but for everyone."

She also noted, "It would be a whole lot easier not to be so public when you're going through something like this." But, she said, her mom told her to be of service to others. And she has heard from many family members going through similar challenges. "It's a privilege to be a messenger."