"We've decided to tell her how we feel and drew straws. I obviously drew the short straw.
"So am I being unreasonable to tell her that we do not want to wear and pay for these monstrosities?"
She goes on to say she knows the bride is "so stressed" and asks for advice on how to tell her they all hate the dresses.
Uploading an image of the offending outfit, she adds that the bride wants them to wear the dress in yellow - a colour she says doesn't look good on any of them.
Rather than really give any good advice, the resounding response from Mumsnet users was to lament how truly hideous the dress in question was.
One wrote: "Everything about that dress is grim! No one will wear it again."
While another joked: "I would wear it for the Lols."
Meanwhile another user seemed to somewhat empathise by commenting: "I don't know how you go about that conversation but they are seriously hideous! You can't wear that!"
And another wrote: "Good god. Nobody could pay me enough to wear that hideous eyesore. As for actually paying for it myself, it'd be over my dead body."