Guest mortified after wedding day mistake caught on camera

A woman has shared a video of the blunder she made as a guest at her friend's wedding. Photo / TikTok: mediocrehailey

A woman has revealed the mortifying "mistake" she made at her friend's wedding – sharing a clip of her unbelievable error.

Wedding guest Hailey shared a video showing her walking up to her friend's wedding cake during the reception and grabbing a knife.

While the cake had already been cut and served up, the top tier had been left untouched as it is tradition for couples to freeze it and eat on their first anniversary.

But without a second thought, Hailey can be seen cutting into the white cake – adorned with a bride and groom topper – and plonking a slice on a plate while licking her fingers.

"My apologies to the bride and groom," she captioned the shock TikTok clip.

Hailey, wearing a red and white polka dot dress, said she was unaware of her blunder at the time – explaining what was going through her mind when she committed the wedding offence.

"Ignoring the brownie table and confidentially [sic] cutting myself a slice of HER WEDDING CAKE thinking, 'Uh-oh! They forgot to serve it to everyone'," she wrote in text over the footage.

"I know better now. I hate myself."

A woman has shared a video of the blunder she made as a guest at her friend's wedding. Photo / TikTok: mediocrehailey

The video quickly blew up, amassing almost four million views and hundreds of comments since it was shared on Tuesday.

One comment came from the bride herself, who reassured concerned viewers the pair were on good terms.

"As the bride whose cake this is – she is formally forgiven and has learned her lesson in wedding etiquette," the woman wrote.

However, the "mortifying" blunder proved too much for some, with many declaring it "insane".

"Did you lose your mind? I hope you found it," one user wrote.

"Honestly this isn't even funny and this is why I will elope because of selfish unaware people like you," another said.

"I would be absolutely mortified," someone else wrote.

Others couldn't believe the person behind the phone who had captured it all on film didn't interject to stop it from happening.

"Why did this person just record you doing that instead of telling you not to?" one asked.

"OK valid mistake but why didn't the person recording stop you?" someone else said.

And another wrote: "I just wanna know why the person videoing didn't stop her."

There were even people who claimed Hailey's mistake was unforgivable, declaring she would be "unfriended immediately".

In response, many argued a slice of cake wasn't worth losing a friendship over.

"As someone getting married in the near future I seriously wouldn't care. It's just a cake, who cares. People get way too uptight over weddings," one said.

"Why is everyone so mad she obviously didn't know," another added.

One more said: "Friends are way more valuable than cake. It would take me two seconds to forgive this."

Wedding etiquette has long been debated, with the most controversial unwritten rule surrounding whether or not you can wear white to a wedding.

Experts argue "no", stating it draws away from the bride, but social media regularly lights up with fury at snaps of guests in the bridal colour.