Robin Roberts Taking Time Off From 'Good Morning America' Ahead of Bone Marrow Transplant

ABC/Fred Watkins

Robin Roberts will be taking a longer break from Good Morning America than originally expected. She announced the news during the first hour of Tuesday's broadcast, noting that she wasn't feeling well.

our editor recommends

'GMA' Finally Ties 'Today' in Demo, Also Winning Among Total Viewers

Robin Roberts Battling Another Health Issue

London 2012: NBC Spoiled Missy Franklin’s Tape-Delayed Olympic Victory With 'Today' Promo

The host, recently diagnosed with blood and bone marrow disorder Myelodysplastic Syndrome, was not supposed to go on leave from the show until late August or early September when she's scheduled to undergo a marrow transplant.

PHOTOS: THR's 35 Most Powerful People in Media

"Well, a full disclosure here, I’m not feeling too well," said Roberts. "In fact I’m going to leave and let you all do the rest of the program on your own. I’m going to take a little time off, just to get some vacay…I’ll see you in a couple of weeks."

Roberts then exaggerated that she was talking out the side of her mouth, which prompted anchor Josh Elliott to commend her on her Jimmy Cagney impersonation.

Roberts had previously scheduled a vacation and is currently set to return to work on Aug. 20.

PHOTOS: The Most Talked-About TV News Faces

For the rest of the week, Amy Robach will be reporting alongside Elliott and Lara Spencer, tomorrow through Friday, with Paula Faris joining as news anchor tomorrow and Thursday and Dan Harris pinch-hitting on Friday.

Looking ahead to Roberts' longer break, ABC News has already announced that Barbara Walters, Diane Sawyer, Katie Couric and Kelly Ripa will be among the faces helping George Stephanopoulos navigate GMA without his co-host.