Marine science technician Zac Edwards, 37, was posing for photos with his beautiful bride Cindy, 32, on a beach when guests spotted a swimmer struggling in the water nearby.
Before they had time to think however, Zac - a former lifeguard and coast guardsman - had ripped his wedding shirt off and jumped into the water to swim out to the boy.
Zac swam for 150 feet before coming to the aid of the 18-year-old swimmer, who had gotten into difficulty while playing on a boogie board in the choppy waters of Orange Beach, beside the Gulf Shores south of Alabama, USA.
The groom however managed to prop the boy up on his board, and get him back to dry land, where he was met by paramedics before the wedding party continued.
"I took off my shirt, but my wife said I didn't have time to take off my pants," Zac said. "She [Cindy] said 'don't worry about your pants, just go'. See you've got to listen to your wife because otherwise, you're in trouble."
Speaking to the Daily Mirror, the groom said: "I told some kids to go back to the beach and I took a boogie board. I’m so glad I did that."
"You could just tell by the look on his face he was in difficulty. When we first saw him he was about 50 yards out."
For the brief time Zac battled the currents in the water, bride Cindy worried he was tiring.
"I could tell Zac was tiring and they couldn't get over the current," she said, before commending the emergency service team who had been called to another emergency further down the beach.
She said she got a "Hero and hubby in the same day" with brave Zac.
"It was incredible," the ceremony pastor said of the dramatic wedding day rescue.
"The fact that this man took time out of his special day to save someone else was really special.
"I talked to Cindy and Zac afterwards and we definitely think it was fate that he was there. It was providential."
The happy couple were relieved the young swimmer was okay but urged others to be more water safety aware.
"I think people underestimate the ocean," said Zac.
"People don’t read the signs and swimmers need to be very cautious. Even experienced swimmers can get into difficulty.