Watch Michael Phelps Talk 'Insane' Great White Shark Race

"They were pretty massive sharks. I had one literally come right up to my nose," said Olympic gold medalist on 'Shark Week' race

Good Morning America

Michael Phelps will begin his battle for ocean supremacy when he races a real-life shark for the Discovery Channel's Shark Week. Phelps shared an Instagram post in which he said being in a cage and diving with a shark was something he "had always wanted to do." 

"When we were in the cage, as soon as I first got in, I felt both sides of the cage kind of moving back and forth, and I was like 'Oh my gosh, we're really getting bit, the cage is shaking,'" Phelps said on Good Morning America. "They didn't look that big underwater. I guess now seeing the video, they were pretty massive sharks. I had one, like I was saying, literally come right up to my nose, and it was crazy."

For obvious safety reasons, one of the main questions surrounding the episode since it was announced has been how the Discovery Channel planned on physically racing Phelps and a shark. Phelps made it clear that he and the shark were not in the water at the same time, though, and that he always had a number of divers around him to make sure he was safe.

"We're not in the water at the same exact time," Phelps explained. "That's the one thing we wanted everyone to know — I was safe. I had 12 to 14 divers underneath me when we were doing the race. When you have an animal this size, you want to be able to see how fast they swim. It’s tough to go into their territory and be able to swim as fast as they do, right?"

Phelps also revealed that he came close to reaching his hand in the water at one point to recover a GoPro before he realized putting one of his limbs in shark infested waters probably wouldn’t be a great idea. Smart guy. We’ll find out if the Olympics prepared him well for shark racing at 8 p.m. ET on Sunday when 'Phelps Vs Shark: Great Gold Vs Great White' airs.