She told fans she was “in the final stages of recovery” following the procedure and “ready to start the next chapter”.
Anastacia, 45, cancelled her European tour in February after the second diagnosis.
She made a full recovery in 2003 after being treated with surgery and radiotherapy.
Anastacia, famous for her hit single, I’m Outta Love, cancelled 13 dates in April across Europe to promote her latest album It’s A Man’s World.
“In light of Breast Cancer Awareness Month I wanted to take the opportunity to support a cause particularly close to my heart,” she said.
“I was diagnosed with breast cancer for the second time earlier this year and am currently in the final stages of recovery after undergoing a double mastectomy.
“It has been an intense journey but I am feeling great and ready to start the next chapter.
“Breast Cancer Awareness Month gives all who are facing this disease a chance to gain strength and support from each other.
“Early detection has saved my life twice. I will continue to battle and lend my voice in any way I can,” she added.
Angelina Jolie revealed earlier this year that she had undergone a preventative double mastectomy to reduce her risk of developing breast cancer.
Sharon Osbourne also revealed in November that she had undergone a double mastectomy.
Image source: Wikimedia Commons President-elect Donald Trump celebrated his election victory at the Ultimate Fighting…
Millions of voters across the US chose to return Donald Trump to the White House…
Donald Trump declares victory in the US election as he addresses jubilant supporters in Florida.…
Stocks around the world are rising as Donald Trump appears to be on the cusp…
Donald Trump has won Pennsylvania, North Carolina and Georgia and taken a lead over Kamala…
Quincy Jones, the celebrated musician and producer who worked with Michael Jackson, Frank Sinatra, Ray…