A bride is furious after her wedding was upstaged during her vows.

In today’s edition of ‘weird s**t people have done at weddings’ a best man has upstaged the bride and groom at their over $100,000 wedding.

The bride wrote into Slate’s Dear Prudence column and explained that after dating, having a child, moving in together, and buying a house – the couple gave into the pressure from their family and friends to get married.

They tied the knot with a lavish wedding, costing upwards of $80,000 USD – but their big day didn’t exactly go to plan.

‘John’, the groom’s best friend, fulfilled the dual role of best man and officiant – and, boy, did John have a surprise up his sleeve.

Right in the middle of the bride and grooms vows, John proposed to his girlfriend 'Jane' and announced their pregnancy to the stunned crowd.

"I couldn't even hear the vows my husband wrote or the rest of the ceremony over Jane's happy sobs, her very surprised family who were also guests, and people seated nearby congratulating her," the bride wrote.

But it didn't end there. During his toast John also made the most of the opportunity, talking about his future with Jane, and barely mentioning the bride and groom. He even demanded the band play a song so he could share a 'special dance' with his new fiancé.

The bride was obviously a little peeved and her new husband hasn't spoken to John since the wedding.

"Our mutual friends think what he did was rude but that my husband should just get over it. My husband joked that he'll resume his friendship when John and Jane five him a $40,000 cheque for 'their half of the wedding'," the bride explains.

When the bride asked agony aunt Mallory Ortberg whether John's actions warrant the end of her husband's relationship with him, she replied that it definitely "merits a fight!"

The crazy extremes of weddings costs. Post continues...

"He’s your husband’s best friend, so your husband should tell John just how upset his behavior during your wedding made him."

Ortberg said there was definitely "at least one step" in between "seething silently" and "cutting John loose forever".

And maybe that step is sending John an invoice for $40,000.

Do you think John did the wrong thing?