Robert Irwin has detailed the toe-curling encounter he had with King Charles as a child.

Speaking with Jimmy Fallon on The Tonight Show, the 22-year-old conservationist reminisced on a royal lunch he shared with a then-Prince Charles years earlier.

He told Fallon he spilled his orange juice across the table in the King’s direction not once, but twice.

“I’ve never really told this one, this is bad,” he began.

“I was at lunch with the King of England, with King Charles, and I’m sitting there as a kid and I’ve got an orange juice.

“I managed to spill it across the table right at him. Luckily, though, I didn’t hit him.

“The best bit is they bring me another pitcher of OJ full to the brim, and I did it again five minutes later.”

Mr Irwin added he was constantly spilling drinks at the dinner table, recalling pointed advice his mother once gave him. 

“I’m notorious for spilling stuff, so my mum would always tell me, ‘Robert, if you were dining with royalty, you wouldn’t spill,'” he said.

“‘So just treat it like you’re always dining worth royalty.'”

Irwin also told Fallon about the time an enormous crocodile named after the talk show host, “death-rolled” him after Irwin jumped on his back during a conservationist study. 

A death roll is a fatal tactic used by the reptile to subdue, drown, or dismember their prey.

He said the crocodile, classified a ‘boss croc’, weighed 317kg and measured more than four metres in length. 

He explained the method he uses to study crocodiles, which involves jumping on their backs, was passed down by his late father, Steve Irwin. 

“We research crocodiles in the wild to better conserve them,” the Dancing with the Stars winner said. 

“The way you do that, my dad actually came up with this, is that you have to jump on them.

“So I jumped on the back of Jimmy Fallon and get this… he death rolled me.”

Irwin said he was momentarily trapped beneath the 14-foot crocodile, unsure how to wriggle free from its crushing weight. 

“I kid you not, 14 foot of crocodile, big croc, death rolls me,” he said. 

“So I’m stuck underneath him with my arm hanging out. I’ve got probably 700 pounds on top of me.

“I’m just like, what do I do?”

In a stroke of luck, ‘Jimmy Fallon’ rolled off of him unprompted, giving Mr Irwin a chance to break free. 

“Luckily, he rolled back the other way and I was fine – but he’s a goer.”