Most people know Michael Phelps is fast - but is he faster than a great white shark?
This is a question which Discovery Channel's Shark Week aims to answer.
On July 24 at 8amSingapore time, Phelps will pit his speed against a great white shark in an event titled Great Gold VS Great White.
Discovery Channel, in a release on their website, dubbed the event "so monumental no one has ever attempted it before", where "the world's most decorated athlete takes on the ocean's most efficient predator".
Phelps, 31, retired after the Rio 2016 Olympic games with 23 Olympic swimming gold medals. He is known for his speed in the pool, with a top speed of six miles per hour (9.7 kmh).
The great white shark has, however, a top speed of 25 miles per hour. This vast difference in speeds has left experts with no doubt as to who the winner of this race will be.
"It is a forgone conclusion as to who is going to come out on top," Tooni Mahto of the Australian Marine Conservation Society told BBC Radio 5 live.
However, this may not necessarily spell doom for Phelps, as no news has been given on exactly what form the race will take.
Mahto said: "We can all be fairly certain it's not going to be Michael Phelps versus a great white shark in an Olympic-size swimming pool."
"I'm assuming it's going to be looking at the human body in water compared to a creature that's evolved over millions of years and is perfectly adapted to its marine environment," she added.
Phelps further fueled speculation on June 11 when he posted a photo on Instagram of a shark and a shark cage, writing: "I was able to do something that I had always wanted to do. Be in a cage and dive with great White sharks!! #bucketlist"
He will also appear in another special on Shark Week - Shark School With Michael Phelps - where he goes to the Bahamas to learn more about sharks.