She explained: "Sister was lame for that she was trying to get revenge because her sister downgraded her from a matron of honour to a bridesmaid."
The wedding guest's tweets have gone viral gaining more than 40,000 likes and thousands of responses.
People were quick to weigh in, with some saying the bride's sister should have stopped her from engaging in the incident in the first place.
One responded: "The right thing would've been telling her sister not to do it instead of watching, recording, and THEN sending it to her fiancé."
Others believed the sister was either jealous or liked the groom herself.
More weighed in supporting the sister.
"Nah her sister did the right thing."
Another agreed: "She could just have integrity and didn't want this man to be hurt knowing he aint deserve it."