By Chris Chase

Note: Post updated with book excerpts at the bottom.

Tennis legend Andre Agassi reveals in his forthcoming autobiography "Open" that he used crystal meth during his playing career, Paul Bogaards, a spokesman for the book's publisher, confirmed to the New York Daily News on Tuesday.

According to the Daily News, the eight-time Grand Slam champion admits using the illicit drug in 1997, the year he married Brooke Shields and went into a career slump that didn't end until 1999.

After pulling out of that slump, Agassi went on to win five Grand Slams and became only the fifth player to complete the career Slam. He has been heavily involved in charity work since retirement, opening his own charter school and championing educational reform throughout the country.