The star says he has been "very unwell" but is now "on the road to recovery."
Gibb's extremely gaunt appearance and the cancellation of several public appearances have sparked fears that he is seriously ill. He was hospitalized last month with colon inflammation and other problems but has been discharged.
The 61-year-old Gibb thanked his fans Wednesday for their messages of support. He said he was grateful for their prayers and good wishes.
The Bee Gees have sold millions of records and are best known for the "Saturday Night Fever" soundtrack which includes the hit "Stayin' Alive."