Image copyright Hatt Photography / Facebook

A wedding photoshoot in Canada took an unexpectedly dramatic turn as the bridegroom leapt into a lake to save a little boy from drowning.

Clayton and Brittany Cook were posing for wedding photos on a park bridge in Kitchener, Ontario, when the groom noticed a boy in distress in the water.

With no thought for his suit, Mr Cook jumped into Victoria Park lake and pulled the young boy on to the shore.

Their wedding photographer captured the rescue.

The images have since gone viral.

Image copyright Hatt Photography / Facebook

"For several minutes these kids were following us, and I was just keeping an eye on them because they were standing close to the water," Clayton told the BBC.

"Then while Brittany was getting her solo shots taken I realised only two were standing on the rock ledge.

"I saw the boy in the water struggling to keep his head up. That's when I jumped down.

"I just kind of plucked him out and he was okay."

Clayton's wife said she originally thought he had jumped in the water as a joke.

"We'd like to think most people would probably make the same choice," she said.

"As soon as I could turn around he had already plunked him on the ground outside the river," wedding photographer Darren Hatt told the BBC.

"So I just kept on capturing the story of the day, including this."

After being rescued, the boy appeared fine, if a little shaken, and went off with an older sibling.

Mrs Cook 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.

"That's Clay to me," she told CTV. "It's something he would just instinctively do."