White is not the worst colour a wedding guest can wear.

There are a few obvious rules about attending a wedding.

Try not to get too ridiculously drunk and embarrass/injure yourself, don’t pash the groom (or bride) and don’t crash the speeches. Oh, and don’t, whatever you do, wear white.

The latter is arguably one of the biggest and well-known wedding guest no-nos – but it turns out it’s not the only colour you should be avoiding.

Even the Mamamia team have confessed to their biggest wedding day regrets. (Post continues after video.)

Diving deep on wedding forums, we discovered that there actually are a number of colours that are even worse to wear than the virginal shade.

The biggest surprise offender? Red.

According to one Reddit user, this is largely because it stands out in pictures thus stealing the limelight from the bride.

Stunning Red…… Miranda Kerr. . #mirandakerr #model #vsangel #victoriassecret #victoriasecret #fashion #style #gfs10000 #makeup #portugal #france #spain #germany #austria #norway #southafrica #brasil #argentina #venezuela #china #india #japan #america #hairstyle #haircolor #reddress #gown #floorlength #vanityfair #clutchbag

A photo posted by gfs10000 (@gfs10000) on Oct 13, 2016 at 6:30pm PDT

Probably, definitely not this one.

In certain cultures and regions like China, red rather than white is reserved for the bride.

Traditionally, the colour red also had a scandalous association.

“The thing about red was more about sex than brightness per se. It used to be associated with being a ‘scarlet woman’ or was supposed to imply you’d slept with the groom,” wrote one commenter on wedding forum Etiquette Hell.

“Yes, it’s quite silly and old-fashioned!”

Who knew? (Post continues after gallery.)

Another colour many believe should not be worn to a wedding is black and again, this dates back to old (and arguably probably outdated) traditions.

“Black stands for the disapproval of the union in a lot of places, so it’s considered rude,” wrote one user.

Others associated it more with funerals than celebrating a supposedly happy occasion such as a wedding.

Some commenters suggested that along with white, no ivory, cream, blush or very pale shades of pastel should be worn to avoid making it look like you’re wearing white in photos.”

“Avoiding patterns on white. i.e white and pink flowers unless the level of white is less than 30%,” advised one Redditor.

Post continues after audio.

“White jackets are fine but remember to take it off for group photos otherwise you look like your wearing a white dress if someone is standing in front of you.”

If that wasn’t enough, many recommended checking what colour the bridal party will be wearing so you can avoid looking like you’re attempting to match them.

“I always try to wear a dress that has a unique feature (i.e. retro, gradient, bow, two-colored,….) so that I will never be confused with the bridal party,” wrote huskergirl.

Image: Universal Pictures

Yep, there's a fair bit to remember.

Fortunately not everyone is a stickler for tradition, with many past brides commenting saying they actually didn't care what their guests wore.

"I didn't care what anyone wore, and for the most part, I didn't even notice. There were a few people who wore bright pink or shades of red, and yes, it did stand out a bit more in photos now that I look closely, but I don't care," wrote one user.

"It's what they wanted to wear, and presumably what they were comfortable in, and that's what I care about."

Bottom line - if you really want to wear that black/red/blush dress but don't want to p*ss off your bride, just ask her. Just don't snog her husband-to-be.

Image: iStock