American Caeleb Dressel has failed in his attempt to become the first man to break the 20-second barrier with the help of the infamous Speedo LZR Racer "super suit".
Dressel participated in an exhibition event for his sponsors, Speedo, which was designed to see how fast a man can go in water without any restrictions.
The event was aimed at marking the 20th birthday Speedo’s Fastskin material.
Dressel took two attempts dipping below the 20-second barrier in the 50 metres freestyle, but could not achieve the feat.
He finished his first attempt in 20.41, with his second timed at 20.40.
The attempts come three weeks on from Dressel leading his Cali Condors team to victory at the International Swimming League (ISL) event in Budapest.
Dressel broke three world records at the event, including the short-course 50m freestyle, where he posted a time of 20.16.
"I had to change a couple of things," Dressel said after attempting to dip under the 20-second mark.
"As soon as I dove in, I would float right to the surface.
"I had to change body position here and there.
"It felt really good.
"I’ll say this as well, the suit doesn’t make the swimmer, the swimmer makes the suit.
"I would 100 per cent do it again.
"It is not about going as fast as you can all the time, it is about learning from the sport.
"I think that is the most important thing I can take away from today."
The attempt was filmed at La Mirada Regional Aquatics Center in California and Speedo released footage of the attempt on YouTube today.
The Speedo LZR Racer suit was made famous at the Beijing 2008 Olympic Games.
The suit was worn by 94 per cent of swimmers who won a gold medal.
It was later outlawed in 2010 by the International Swimming Federation, with male swimmers prevented from wearing full body suits and forced to revert to the current knee-length jammer shorts.