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FILE - In this Aug. 28, 2016 file photo, Michael Phelps poses in the press room at the MTV Video Music Awards in New York. Phelps will be named Sports Illustrated's "Person of the Year" at a ceremony on Monday, Dec. 12. (Photo by Evan Agostini/Invision/AP, File)

Michael Phelps

Olympic champion Michael Phelps has announced his intention to retire after the London Olympics.