Rosie Hardy, a wedding photographer in the United Kingdom, told ABC the scene played out earlier this month just after she had gathered all the bridesmaids in their formal-wear to take photos.
"Just as we were about to start shooting, we heard this AWFUL squawking coming from some geese a few feet away," she said via email, "and saw a big black swan lunge at one of their two goslings and start trying to drown it."
That's when one of the bridesmaids, Faye West, jumped into action, wading knee-deep into the lake.
"It was incredible, though everyone did go into a few moments of shock," she said, "as a bridesmaid in a lake isn't usually a good sign!"
West returned the gosling to its parents and emerged from the lake to cheers.
"As she came to shore and returned the shaken little gosling, everyone cheered and we continued on with the portraits," Hardy said, "not before the two geese let out two mighty honks of appreciation though!"
Hardy captured photos of West in the lake and getting her dress wrung out after the rescue, which have been shared hundreds of times on Facebook. She praised West's actions, writing, "Faith in humanity: restored. What a hero!"
West commented on the photo that the gosling was all right after the rescue and she went back to check on it the next morning.