For the rest of the occasion you spend your time avoiding the other person, desperately dodging being in the same photographs.
See also: Scamwatch: surge in wedding fraud
But this was the case for six different women when they all attended the bride's special day wearing exactly the same dress.
And they weren't even the bridesmaids.
The dress cost nearly £100 and was by Forever New, an Australian clothing line.
Sydney resident Debbie Speranza posted the hilarious photo onto the brand's Facebook saying: "You really should start a bridal registry so that your customers can inquire whether anyone else has purchased one of your dresses for the same event.
"No we are NOT the bridesmaids just the guests."
On her personal page she wrote: "Who wore it best???? #backupbridesmaids"
Debbie said she only knew one of the women, her cousin, and the rest were complete strangers.
A friend asked Debbie whether it was planned and she replied saying: "Not at all, I thought it was hilarious. Once we all stood together all the wedding guests were wtf!"
Ms Speranza also joked to the retailer: "Think I deserve a gift voucher for all this advertisement."
Now her post has gone viral, with over 38,000 likes and over 9,000 comments after having people in hysterics.
Elena DiBella Saadie said: "Omg! Deb that's my worst nightmare [crying laughing emojis] You do look great though."
Tammy Roosen said: "I love this. More people should be backupbridesmaids!"
Janelle Reilly said: "I thought oh wow I love their bridesmaid dresses! Lol .. just shows you all have good taste!"
Mary Adams tagged her friends and said: "You should show this to Lauren, so she can show the woman who got really upset when Lauren wore the same dress as her at a wedding!
"These ladies look like they were really good sports about it."
Robyn O'Keeffe said: "Would have been worse if the bridesmaids also had that dress."
Abby Ching posted: "This is amazing. If it was a school formal I think all the girls would have had a melt down."