'Unbelievable': Gymnastics world stunned by never-before-seen feat

American gymnastics superstar Simone Biles has left viewers gobsmacked after a never-before-seen moment in her balance beam routine.

The 22-year-old gymnast made history as the first person to ever attempt, and land, a double-double dismount from the beam.

The history-making moment took place at the US Gymnastics Championships in Kansas City, where Biles is chasing her sixth national title.

Simone Biles' never-before-seen moment stunned the world of gymnastics. Pic: Team USA/Getty

Team USA confirmed the skill would be named after Biles once she completed it at an international meet.

It would mark the third skill named after the 22-year-old considered to be arguably the greatest gymnast of all time.

“I’m really happy with the beam dismount and how it’s come along, because if you had asked me after (US Classic) if I was going to compete it, I would’ve said no,” Biles said.

“I feel like in those short two weeks we did a lot of work on a couple of the events, so I’m pretty excited with how it turned out.”

Biles' extraordinary feat left viewers in a spin on social media.

That wasn't Biles' only history-making moment on Friday, however.

Before her beam routine, Biles also became the first woman to perform a triple-double in the floor exercise.

The American superstar is the most decorated female gymnast of all time, having won 25 combined Olympic and World Championship medals, among countless others.

With agencies