Apparently her betrothed friend was concerned her red hair would prove too much of a distraction.
She continued: "This had never been mentioned to me. I'm a natural ginger, so it's not like I have an outrageous hair colour, although Ella and her other bridesmaids are all brunettes.
"I texted Ella about it, she told me my hair would clash with the wedding colours and that brides get a veto over pretty much every aspect of her bridesmaids' appearances.
"She also mentioned my hair is quite 'attention-grabbing' and I'd take away from the cohesiveness of the group.
"I told her I wasn't comfortable dying my hair. She said she'd get back to me but hoped I'd reconsider."
Reddit users who commented on the post were almost unanimous in their opinion that the bridesmaid should refuse the request.
Despite the Reddit recommendations to refuse the request, the bridesmaid admitted she is considering the dye job.
She ends her spiel by asking: "#Am I being reasonable here? I've never been involved in a wedding before so I'm not quite sure what's expected of me.
"I've gotten some messages from the other bridesmaids who are telling me I should just do it."
The post has been read more than 473,000 times and attracted over 850 comments.
Reddit user Punfree commented that dying her hair may actually make it stand out more than it would if left natural.
"Everybody that knows bridesmaid will be more drawn to the change, it will actually detract from the bride to have such a big appearance change like that on display."
One woman who said she was also planning her wedding implored the bridesmaid to stand her ground.
User Tsukii wrote: "You are not being unreasonable at all! I'm planning my wedding now, and I'd NEVER ask bridesmaids to dye their hair! This is bridezilla-level s***, like she's scared of being upstaged by her 'maids, so she's making crazy demands."