Valerie Harper -- STANDING TALL in the Face of Terminal Cancer

Valerie Harper is refusing to go gently into that good night ... continuing to go out in public and live her life after being diagnosed with terminal brain cancer.

The "Mary Tyler Moore" actress was pictured out in Santa Monica early Thursday morning with her husband of 26 years Tony Cacciotti ... sporting a brave face.

Earlier this week, 73-year-old Harper revealed she has leptomeningeal carcinomatosis, a rare form of cancer in which cancer cells spread into the membrane surrounding the brain.

Rage against the dying of the light.