There’s only one rule – don’t wear white!

Fashion police on Reddit are scolding an anonymous wedding guest for wearing a white gown to nuptials.

“She looks absolutely gorgeous.... except she’s not the bride” Redditor DBear423 wrote on the ever-popular Wedding Shaming forum on Saturday, posting a photo of a woman in an ivory lace gown, posing with a man in a navy suit.

The style slip has since gone viral with over 8,400 upvotes and hundreds of questions, as users wondered how the fashion fail unfolded.

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“This isn’t even just an inappropriate white dress. It’s a wedding gown. It even has a train,” one commenter wrote. “It would be a shame if someone accidentally spilled a glass of Cabernet on that.”

“That’s what bridesmaids are for,” another teased in reply.

“I don't know anyone this selfish but if I did, I'd have my bridesmaids fighting each other to spill red wine on her,” another jokester agreed.

Speculation swirled that the woman in the dubious dress was the sister of the groom, and perhaps received permission to wear the white hue.

“Looks like that’s the MOH or a bridesmaid and if it is they would’ve gotten the OK from the bride,” one guessed, acknowledging that the uncommon practice is becoming more popular.

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“Those pictures make it seem like it was clearly a planned thing that the bride was probably okay with. The dress matches the bloke’s ties,” another argued. “If it was a regular wedding guest that turned up like that, then absolutely it’d be horrid, but I get the feeling that mightn’t be the case here.”

Another Redditor pointed out that mothers or grandmothers of the bride sometimes wear a “more modest” white dress on the big day, “as a lineage sort of thing.”

“It's not something I'd particularly like to see happen at my wedding, but I think it's an okay tradition or whatever,” they said.

Nevertheless, critics contended that the outfit was still offensive.

“Her dress is outshining the bride a little,” one declared.

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