What happened when Michael Phelps raced against an average swimmer

Olympic great Michael Phelps abilities compared to the average swimmer have been revealed.

American swimmer Phelps is perhaps the greatest Olympian of all time alongside athletes like Usain Bolt and Simone Biles.

The 39-year-old has an incredible 28 Olympic medals, more than any other athlete, with 23 of them being gold.

But what would happen if Phelps were to race against a normal person?

This very question was answered when Phelps appeared on an episode of TheEllenShow in September 2016 to train and race against the show's executive producer Andy Lassner.

In a segment of the show named 'Average Andy,' some of the most extraordinary people in the world spend time with Andy to show him their talents.

And in this episode, he competes against Olympic great Phelps and the difference in quality between the two men is immediately apparent.

Before the race, the pair warm up in the pool by doing lengths and, while Andy is clearly trying as hard as he can to swim quickly, Phelps is able to stay ahead of him while swimming in slow motion.

And the difference only became more clear once the race began.

Within moments of touching the water having dived in, Phelps established a lead of several seconds.

In fact, Phelps' dive was so impressive, that he barely even needed to come up to breathe before reaching other side of the pool.

Meanwhile, Andy is clearly struggling behind the Olympian as he combined front crawl, butterfly and doggy paddle to try to make it to the other end of the pool as quickly as possible.

Michael Phelps is widely regarded as the greatest Olympian of all time. (Image: Getty)

Ultimately, the producer's attempt to compete with Phelps is in vain, as the Olympic swimmer completes the race several seconds before Andy even reaches the halfway point.

By the time he reaches the finish line, Phelps is waiting while laughing and offering his opponent a high five to congratulate him.

Shortly before appearing on the show, Phelps had announced his retirement from competing in swimming after winning five gold medals and one silver medal at the 2016 Rio Olympic Games.

"Done, done, done — and this time I mean it," he told the TODAY Show.

"I wanted to come back and finish my career how I wanted and this was the cherry on top of the cake."