Jon Hamm -- Don't Worry, My House Didn't Burn Down

Firefighters raced to Jon Hamm's Los Feliz home this morning after a smoke alarm went off ... but fear not, TMZ has learned the "Mad Men" star was never in any real danger.

Two fire trucks rolled up at 9:19 AM and firefighters went inside ... by 9:22 AM, they were on their way out after determining the whole thing was a false alarm.

We spent 10 minutes trying to think of a Jon Hamm "fire hose" joke ... but couldn't -- so, feel free to insert your own here.

Have a great Monday.