Alicia Witt underwent cancer treatment shortly after parents' sudden deaths

Instagram - @aliciawitty

Alicia Witt has revealed she was battling cancer at the time of her parents' sudden deaths late last year.

The actress took to Instagram on Wednesday to share a series of photos of her undergoing chemotherapy, including one snap of her celebrating the completion of her final round, while in hospital.

In the accompanying caption, Alicia explained that she finished the treatment prior to undergoing a mastectomy after discovering she had cancer in her left breast.

"Just a little over 2 months ago, I had my last round of chemical therapy prior to my mastectomy. My beloved, brilliant, collaborative, communicative doctor, @habibdoss at @tnoncology, was there to celebrate with us as I rang the bell!" she wrote. "Although we didn't yet know for absolute certain until after the mastectomy that the disease was completely healed from my left breast, this marked the end of my carboplatin/taxotere, + herceptin/perjeta (the latter two are immunotherapies which will continue, per protocol for HER2+, through the end of this year)."

Alicia went on to thank her "tiny crew of human angels" who supported her during the six treatments and recovery from surgery. She also credited them for help keep her diagnosis private until she was healed.

"I'm so grateful to all those along the way during treatment who honored me by protecting my privacy during these months and grateful to help share that these caps can truly play a huge role in allowing a patient to reveal her journey on her own time, when she is ready," the 46-year-old continued. "For me, this was such a needed part of my healing - particularly given the horribly public tragedy that had happened in our family just as I was beginning my treatments."

Last December, Alicia's parents, Diane and Robert Witt, were found dead at their home, with the cause of death reported as "probably cardiac dysrhythmia" due to an improperly heated home.

In light of the news, the star noted that her parents were fiercely independent and refused any help with home repairs.