Good Morning America co-host Robin Roberts announced on Monday that she will be undergoing a bone marrow transplant in early September, and that her last day co-hosting GMA will be this Friday.

The beloved morning show personality announced in June that she’s been diagnosed with a rare form of leukemia that would require a bone marrow transplant for treatment.  Fortunately, her sister is a perfect match and Roberts will undergo the procedure next month. The treatments and recovery are expected to take up to four months.

During her absence, ABC is expected to rotate a series of weekly guest hosts to fill in for her.  Some names mentioned have included former hosts such as Charlie Gibson, Diane Sawyer and Joan Lunden, as well as Barbara Walters or Katie Couric.

ABC on Monday announced that Robin’s team and her doctors will post information on her recovery in the months ahead and viewers will be able to leave personal messages for Robin on a link they will share on Thursday. There will also be information on how to become a bone marrow donor through BeTheMatch.org.

Roberts successfully battled breast cancer five years ago.

Best wishes to Robin on a healthy recovery!