Thomas Haden Church -- Yeah, I Saved a Guy's Life ... No Biggie!

Thomas Haden Church is not the kind of guy to save a human life and then go brag about it on camera ... he's the kind of guy to save a life and then play it off like it's no big deal ... on camera.

According to our sources, Church was having lunch yesterday at the Soho House in Los Angeles, when a guy at a nearby table started choking. We're told Church sprung into action, administered the Heimlich Maneuver and saved the guy's life.

HERO!!!

Our photog caught up with Church later in the day and asked about his lifesaving maneuvers, but the actor was just too damn humble to get into the details.

Church did get his props at lunch, however ... the Soho House comped his meal.