Now this is just rude.

A UK woman cancelled her brother's wedding without his knowledge all because she didn't like her sister-in-law-to-be, the Plymouth Herald reports.

Ann Duffy, 50, called the Plymouth Register Office back in November 2013, just 20 days before her brother's big day. Impersonating her now-sister-in-law, Duffy let the office know she wanted to cancel the wedding, a local court recently heard.

The master meddler then called her brother to fill him in on what she had done: “You better put this on speakerphone. I have saved you on the divorce," she said. "I have cancelled your wedding. Would you like me to send you the confirmation email?”

Unfortunately for Duffy, her big plan didn't go quite as she had hoped. Her brother's financée promptly called the police to report the incident and the couple was able to rebook the wedding the next day.

Duffy -- who said her relationship with her sister-in-law became strained after mother moved in with the couple -- will be sentenced on harassment charges for this, and other incidents, next month.

This sneaky lady's certainly not the first meddling in-law who's made the news for trying to drive a wedge between a couple. In 2011, an Italian bride didn't find out that her new mother-in-law intended to join them on their honeymoon until she arrived at the airport. The unimpressed bride asked for a divorce a few weeks later, AFP reported.