Michael Phelps understands completely that his greatest competitor is himself - specifically, his tendency to let alcohol get the best of him. On Wednesday, the 30-year-old Olympics medalist revealed that he has promised not to drink alcohol until the 2016 Rio Olympics is over.

The bemedalled swimmer said he is serious in making some serious lifestyle changes before hitting the pools at the 2016 Summer Olympics, Bleacher Report has learned.

Phelps revealed that he has sworn never to drink alcohol again until the Olympics has wrapped up. The 18-time gold medalist said he made this promise before going to court for his lartest drunk-driving case.

"Before I even went to court, I said to myself that I'm not going to drink until after Rio - if I ever drink again," Michael said. "That was a decision I made for myself. I'm being honest with myself."

Regretting his past mistakes, Phelps went on to say: "Going into 2008 and 2012, I didn't do that. I didn't say I was going to take a year off from drinking and not have a drink."

This is a big thing for Michael Phelps since alcohol has led him into big trouble with the law for two times now. His first run-in was when he was just 19, he failed to halt at a stop sign. Maryland state troopers had to chase Phelps in Salisbury, Maryland at the time, as per Washington Post.

Phelps pleaded guilty during the trial of his first DUI case and he was asked to serve an 18-month probation.

In Oct. 2015, the U.S. swimmer made headlines for his second arrest over DUI charges. This caused him a 6-month probation.

At the time of his arrest in late September, Phelps took to social media to express his understanding of the situation, saying: "I understand the severity of my actions and take full responsibility. I know these words may not mean much right now but I am deeply sorry to everyone I have let down."

At 30, Phelps now has grasped the importance of maintaining his sobriety as alcohol has caused significant setbacks in his career as an athlete, according to For The Win!

"If I'm going to come back, I need to do this the right way. I've got to put my body in the best physical shape I can possibly get it in," he said.

Michael Phelps then continued: "It is a challenge? No. I go to bed earlier. I sleep more. I wake up every day and have a completely clear head. I don't feel like my head went through a brick wall. There are so many positives to it."

Having promised to maintain his sobriety for the 2016 Rio Olympics, fans are hoping Phelps will get the positive results he is after.