The I'm Outta Love star, 45, announced the second diagnosis in February, cancelling her planned European tour.
Now she has updated fans on her recovery as part of Breast Cancer Awareness Month.
She said in a statement: "In light of Breast Cancer Awareness Month l wanted to take the opportunity to support a cause particularly close to my heart.
"l 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."
She added: "It has been an intense journey but l 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 anyway I can."
Anastasia, who said she underwent a double mastectomy with Latissimus Dorsi flap surgical procedure, was first diagnosed with the disease in 2003.
Angelina Jolie revealed earlier this year that she had undergone a preventative double mastectomy to reduce her risk of developing breast cancer.
X Factor judge Sharon Osbourne revealed in November that she had undergone a double mastectomy.
She beat colon cancer a decade ago but opted for surgery after finding she carried a gene which increased the risk of developing breast cancer.
Former Liberty X singer Michelle Heaton had a double mastectomy late last year after she was diagnosed with a mutated BRCA2 gene, which meant she had an 80% chance of developing breast cancer and a 30% chance of ovarian cancer.