United Kingdom, Aug. 8 -- Kelley Mack's death came as a "total surprise" to those close to her.

The Walking Dead actress passed away on 2 August at the age of 33 after being diagnosed with glioma, cancer of the central nervous system, in February, but she had been feeling much better in the months leading up to her passing.

A family source told TMZ that Kelley - whose real name was Kelly Klebenow - had experienced a "nice recovery" after undergoing treatment but she relapsed "out of nowhere", with the disease spreading through her body in recent weeks, leading to a "quick end".

The 9-1-1- actress spent an "immense" amount of time with her family and friends leading up to her death and was still working on voiceover jobs just a month ag...