Vampire groups have put out a warning to Megan Fox and Machine Gun Kelly after Fox announced they had been drinking each other's blood.

In late April, the world learned information it probably wasn't quite prepared for. Actor and model Megan Fox told Glamour Magazine that she and her fiance – musician and actor Machine Gun Kelly – drink each other's blood as part of unspecified "rituals".

“So, I guess to drink each other’s blood might mislead people or people are imagining us with goblets and we’re like Game of Thrones, drinking each other’s blood,” Fox told Glamour. “It’s just a few drops, but yes, we do consume each other’s blood on occasion for ritual purposes only.”

She reiterated that it was only a few drops, whereas "he’s much more haphazard and hectic and chaotic, where he’s willing to just cut his chest open with broken glass and be like 'take my soul."

It was never going to be long before people started issuing health warnings, but in a fun(?) twist on the story, these health warnings come from self-proclaimed vampires.

Belfazaar Ashantison, co-founder of the New Orleans Vampire Association (NOVA) – an organization created "to provide support and structure for the vampire and other-kin subcultures and to provide educational and charitable outreach to those in need" –  told TMZ that the couple should take proper precautions before drinking each other's blood, including regular tests for diseases.

He made it clear this was because (human) vampires are not immune to human blood-borne illnesses.

Meanwhile, the founder of Endless Night Vampire Ball told the publication the couple should be especially careful how they draw their blood, relying on medical professionals rather than Machine Gun Kelly's proposed shards of glass method.

Of course, there are quite a few reasons why you shouldn't consume blood from a medical perspective. Should you chug enough iron-rich blood, you could even end up giving yourself an iron overdose. Drink far too much and it could, in theory, kill you.

For the casual blood-drinker, there are risks too. Though the US Centers for Disease Control and Prevention (CDC) doesn't have specific advice on consuming blood, their advice for intravenous drug users sharing needles applies here. Drinking blood will put you at risk of blood-borne illnesses – primarily HIV and Hepatitis A, B, and C.

Should Fox and Kelly not already be taking these precautions, maybe it will give them pause for thought to know that even people who believe they are vampires are telling them to cool it.