Terry McGlade was injured when a roadside bomb went off in Afghanistan, and suffers from Post Traumatic Stress Disorder and seizures as a result. His dog, Major, managed to call for help from the emergency services, saving his owner's life.
But rather than barking or whining, Major actually dialled 911 to call an ambulance to the scene, later meeting the crew outside the house and leading them to his owner in the back garden.
'Right now he's my world because he's basically an extension of my body, I don't think I can operate in an everyday world without him right now' says Mr McGlade.
Major is a rescue dog trained to sense when Terry's seizures are coming on - but was never specifically trained on how to use a mobile phone, which is why his story is so incredible.
He is a pit bull and labrador mix.
They don't call them man's best friend for nothing! Watch the incredible video above.