Here's the moment Heather McDonald suddenly collapsed in the middle of her comedy set ... and the video looks, and sounds, painful.
The comedian just addressed the moment she fainted onstage during a sold-out show in Tempe, AZ ... sharing talking about the incident Tuesday on her podcast, "Juicy Scoop." We've received video from the segment showing the scary situation.
As you can see, Heather is just finishing up a joke when she collapses to the floor.
Heather says she's still not sure why it happened ... though she says she didn't eat before her weekend set and only drank half a Red Bull and some water. Heather also shot down rumors someone might have spiked her drink.
TMZ broke the story ... Heather fell hard onstage and hit her head, suffering a skull fracture.
Heather says she got a cat scan and a battery of other tests, all of which she says came back totally normal.
It's been a few days since the fall, and Heather says she now has 2 black eyes, plus some internal bleeding in her head ... but everything is healing.