Spencer Pratt and Heidi Montag have lost their home in the massive wildfire that's currently burning on Los Angeles' westside ... TMZ has learned.

Sources close to the reality TV stars tell TMZ ... their Pacific Palisades home burned to the ground on Tuesday as a massive wildfire tore through the celeb filled neighborhood. We're told the entire family was able to safely evacuate earlier in the day to another location but are devastated by their loss.

Spencer shared a video to his Instagram Story hours before having to evacuate in which you see fire officials dumping water from above onto the nearby mountainside to try to contain the blaze. Spencer was photographed outside his home where he understandably looked upset and in distress as he watched the fire spread.

As we've reported .... a fast moving wildfire that's now burned more than 1,200+ acres and sparked mandatory evacuations began burning through the neighborhood earlier today. Actor James Woods filmed the growing inferno from his home in the neighborhood. In the video you see firefighters dropping water on the area as he stands by in his driveway.

Tons of celebs live in the area including Tom Hanks and Rita Wilson, Miles Teller and his wife Keleigh, Reese Witherspoon, Adam Sandler, Steve Guttenberg, and Michael Keaton, among others.

Officials have not yet said what caused the wildfire.