The singer announced on Twitter over the holidays doctors forced her to reschedule her comeback tour dates.
According to Yahoo! News, Janet Jackson is undergoing tests for throat cancer.
The singer, who was scheduled to begin her 'Unbreakable World Tour' on January 9, postponed the first few tour dates after a tumor on her vocal chords was discovered by doctors.
Janet Jackson Puts 'Unbreakable Tour' on Hold for Vocal Rest
"Doctors found a growth on Janet's vocal chords that could be serious," a source said. "It's a medical condition that has to be taken care of immediately."
On Christmas Eve, the 49-year-old revealed on Twitter that she was "forced to postpone the Unbreakable Tour until the spring" and promised each ticket holder that "every date [would] be rescheduled."
Jackson also asked for prayers for herself, her family, and the crew involved with her tour during this time.
"I love you all so much and am ever grateful for your understanding and your love," she added.
We love you too, Janet! Get well soon!