Robin Roberts says she arrived to her mother's bedside in the nick of time after leaving "Good Morning America" on Thursday ... and got to "hold her sweet hand when she took her last breath."
Roberts -- who was recently diagnosed with a rare blood disorder -- had decided to go on medical leave one day early after her mother's health took a turn for the worse.
Robin's mother died Thursday night ... but Robin went to Facebook to tell her fans she DID get to see her mom before she passed away.
"My family tells me momma gave me one final gift as her last act. She waited for me to get home on Thursday to say goodbye."
Roberts adds, "She was there when I took my first breath and what a privilege to hold her sweet hand when she took her last breath."
"Momma knew she wasn't physically able to be with me for my bone marrow transplant. My siblings say mom wanted to spare me the agony it would have been if she had passed and I couldn't be there. That thought was weighing heavily on me."
Roberts says she rescheduled her bone marrow transplant because of her mother's passing ... but says, "When I return to NYC and walk through those hospital doors next week momma will be right there with me."