What happened to Kelley Mack? "The Walking Dead" Actress reportedly recovered after cancer treatment before relapsing weeks before her death 

Actress Kelley Mack, known for her roles in The Walking Dead and Chicago Med, reportedly died in Cincinnati on August 2, 2025, at the age of 33. Her death came after a months-long battle with glioma of the central nervous system. According to Mayo Clinic, glioma is a type of tumor caused by the "growth of cells that starts in the brain or spinal cord."

A TMZ report published on August 7, 2025, states that Kelley Mack apparently made a full recovery from her cancer before suddenly relapsing weeks before her death. A source told the publication that Mack experienced a "nice recovery" after treatment for glioma in February 2025. However, she relapsed in the weeks leading up to her death as her cancer spread throughout her body.

The source also said that Mack had a "quick end." Meanwhile, Kelley Mack's representative told TMZ that her death was sudden and unexpected, adding she had been auditioning for new roles in June. The rep also claimed that while Mack told her team she needed a break from auditioning in July, "no one expected" her death.

Besides being an actress, Kelley Mack was also a voiceover artist and screenwriter, working with her mother, Kristen Klebenow, on various full-length scripts. She was known for playing Addy in the ninth season of The Walking Dead and appeared in films such as Delicate Arch, Broadcast Signal Intrusion, and Universal.

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It’s with immense sadness that we share the passing of Kelley Mack at the age of 33. Kelley is known to fans of #TheWalkingDead for portraying the character of Addy in Season 9. Our sincere thoughts are with her loved ones during this difficult time.

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Kelley Mack's family to hold a life celebration on August 16

Kelley Mack's family is set to hold a celebration of life for the late actress in her hometown of Ohio on August 16, 2025. Mack's sister shared this information in a social media post announcing her death on August 5, 2025.

In the caption, her sister expressed the "indelible sadness" of sharing the news of her sister's passing, adding that a "bright, fervent light has transitioned to the beyond, where we all eventually must go." Kelley Mack's sister also mentioned that she was surrounded by her mother and aunt at the time of her death, writing:

"Kelley passed peacefully on Saturday evening with her loving mother Kristen and steadfast aunt Karen present. Kelley has already come to many of her loved ones in the form of various butterflies. She will be missed by so many to depths that words cannot express.

"Kelley’s Caringbridge link in her bio includes the 2-page formal announcement with information on her upcoming life celebration in Ohio on August 16th. She would want you all to know how much she loves you. And as her sister, I want you all to know how brave that tough SOB was, especially when she decided to make the leap to be reunited with God. I’m so f**king proud of her."

Kelley's sister's post (Image via Instagram/@itskelleymack)

In January 2025, Kelly Mack took to Instagram to tell her followers she had been diagnosed with diffuse midline glioma, a rare type of astrocytoma cancer, after experiencing persistent lower back pain since late 2023. Mack expressed gratitude for the support she received and mentioned that she planned to pause her acting career while undergoing radiation treatment in Cincinnati.

Following this, she often shared updates about her health journey on her Instagram to keep fans informed about her treatment and recovery.

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Kelly Mack's last Instagram post before her death was about her upcoming film, Universal. On June 22, the actress shared on Instagram that the movie was set to premiere at Dances With Films at the Chinese Theatres in Los Angeles that night. The film, directed by Stephen Portland, stars Kelley Mack and Joe Thomas.