Clayton and Brittany Cook were posing on a park bridge in Ontario, Canada, when the groom noticed a distressed boy in the river.
Without a moment's hesitation, Clayton jumped into the water and pulled the young boy onto the shore.
The wedding photographer, Darren Hatt, captured the whole rescue and the images have now gone viral.
Hatt said the groom's reaction was so quick, be barely had time to take the photos.
He shared to Facebook, 'By the time the bride noticed and shouted out, Clayton had already jumped down and brought him to safety. His quick action saved the little guy who was struggling to swim. Well done sir!'
Clayton later told CTV News: 'His face was underwater and he was fighting, like he was really fighting. Lucky he was only a little guy...and I honestly sort of hopped him up.'
Brittany said her husband's quick thinking and selfless action were just some of the reasons she fell in love with him in the first place.
She told CTV: 'That's Clay to me, it's something he would just instinctively do.'