The mother-in-law email that went viral is not a hoax insists Freddie Bourne.

Freddie Bourne denies that the email his mother sent to his fiancé describing her as uncouth was a hoax.

Carolyn Bourne sent her future daughter-in-law, Heidi Withers, a scathing email in late June, insulting her for a lack of ladylike behaviour.

Father of bride to-be hits back at mother-in-law over viral email

But after London's The Observer reported that Freddie Bourne was a shareholder in a catering and event planning company, there has been much speculation over whether the nasty exchange was real, or merely a publicity stunt.

Mr Bourne’s business website, which has been removed, invited clients to “have the wedding of their dreams” and that "your wedding will be one of the most important days of your life."

Amid the speculation, Freddie Bourne has "categorically" denied that he fabricated any parts of the email exchange.

"[The business] has been running for two years and I only became involved one month ago," he told the Daily Mail.

In the original email, Carolyn Bourne criticized Heidi, outlining several instances of her lack of manners.

“You do not remark that you do not have enough food. You do not start before everyone else. You do not take additional helpings without being invited to by your host,” she wrote.

In the email, she also attacked Heidi's parents for not saving enough money for her upcoming wedding and called her a prime candidate for TV program Ladette to Lady.

"One could be accused of thinking that Heidi Withers must be patting herself on the back for having caught a most eligible young man…I pity Freddie,’" she concluded.