Michael Phelps will be swimming in the 4x100-Meter Medley Relay on August 4th at 3:27PM EST, his last competitive race. The star Olympian began his first Olympics during the 2000 Sydney games, and will be retiring after 12 years of unprecedented success.

Michael Phelps entered the 2012 London Olympics with a slow start compared to his 8 gold medals wins in Beijing 4 years ago. However, Phelps began to score golds Tuesday when he won his 19th medal, becoming the most decorated Olympian of all-time. Currently, Phelps holds 21 medals, 17 of those being gold.

After his final race in the 4x100-Meter Medley, Phelps may add to his collection and further advance his record and legacy.

Phelps swam in his last individual race, the 100-Meter Butterfly on Friday. The US swimmer's eyes swelled with tears as he stood on the podium earlier that week for one of the final times in his Olympic career.

"Going into the relay, it'll probably kick into my head more and more," Phelps said regarding his retirement.

Catch Phelps in action on NBC TV broadcasting at 8PM EST.

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