A young girl in Mexico had an unconventional third birthday party when she selected The Nun as the theme for the get together.

Lucia Brown stunned social media users in their thousands after her cousin shared pictures from the event, where the young girl dressed as the title character from the spooky film.

“So it was my cousins 3rd birthday and instead of having a normal theme she chose this," Andrea Villarreal, from San Antonio Texas, tweeted.

More than 500,000 people 'liked' the tweet, while thousands more left comments, including the Twitter account of television show The Walking Dead.

The Motion Picture Association of America rated The Nun NC-17, but it didn't appear to scare young Lucia.

“She chose this theme because she had seen the DVD and I guess the picture had interested her, so she insisted on watching it and she saw the whole thing without getting scared," Andrea told the Press Association.

“I guess the lesson that we can take from her birthday is that you should do what makes you happy no matter what others may think."

Lucia Brown enjoys her third birthday party dressed as a character from The NunLaura E Brown

Andrea continued:

“All that matters is being true to yourself."