1 / 50

Phelps secretly took plunge in June, marrying girlfriend

FILE - In this Aug. 9, 2016, file photo, United States' swimmer Michael Phelps celebrates winning his gold medal in the men's 200-meter butterfly with his fiance Nicole Johnson and baby Boomer during the swimming competitions at the 2016 Summer Olympics, in Rio de Janeiro, Brazil. The Arizona Republic reported Oct. 26, 2016, that Phelps and Johnson secretly married on June 13, 2016. (AP Photo/Matt Slocum, File)

Michael Phelps

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