Watch this heartwarming clip of a heroic service dog doing exactly what he was trained to do and saving the day.

Aubrie Lewis, 31, from Clayton, North Carolina, USA, captured the powerful moment her dog Ducky alerted her that something was wrong, even before the tech did.

Her four-year-old son, who has type 1 diabetes, was upstairs when Ducky suddenly sat beside his owner, refusing to budge.

It was a full 30 minutes before her son’s blood sugar officially dropped but Ducky already knew.

The clip has racked up thousands of views and emotional reactions online.