Last night on "Running Wild with Bear Grylls," actor Zac Efron went skydiving, rappelled off a cliff, and shared yet another classic, gross meal with the survivalist

"A reliable source of food is always under the ground, in the earth - good old worms," Grylls told Efron, handing the star one half of a worm he had just bitten in half. "'Just remember you've got to chew it - you don't want it wriggling all the way. Otherwise it might crawl out of like a weird orifice or something."

Turns out that worm was just an appetizer for the main course - a worm omelet with bird eggs, shells and all. 

"Sometimes I cook up these wilderness meals and get quite excited, I think, ''You know what, this is gonna be amazing'," Grylls informed Efron. "But I'm not gonna sugarcoat it - this is one of the ones that I know is gonna suck." To his credit, Efron was a good sport, eating his worm omelet and, as expected, later describing it as "gross" and "bitter." 

Thankfully, Efron brought s'mores for dessert; which Grylls admitted he'd never tried.

"Unbelievable," Grylls exclaimed. "I can't believe I've never had that before. That beats worm omelets any day."  

From what I've managed to gather online, worm omelets are reportedly a recipe often taught to British soldiers as a survival tactic. Back in 2003, a published study by The Royal Society found earthworms to be high in protein and calcium, as well as a source of iron, magnesium, potassium, phosphorus and copper. It's no wonder they're an easy go-to food if you're stranded somewhere - or sharing a cave with Bear Grylls. 

But let's get to the part you've been waiting for: how to cook up your own worm omelet. Not surprisingly, there's a YouTube video for that. 

Michael d'Estries ( @michaeldestries ) covers science, technology, art, and the beautiful, unusual corners of our incredible world.

Zac Efron just ate a worm omelet and so can you
Actor took on the unusual meal while dining with Bear Grylls on 'Running Wild.' Here's how to make your own at home.