The legendary performer took action after seeing a high and paranoid Versace at one of his concerts, according to "House of Versace" by Wall Street Journal reporter Deborah Ball. He recruited the drugged-out designer's daughter, Allegra, using her party as a front.
The intervention didn't start out as planned -- Versace snorted a line of coke in the bathroom moments before the singer arrived. However, it ended well: Versace ultimately agreed to seek help and flew that night to The Meadows, a rehab center in Wickenberg, Ariz.
According to the book, Versace's drug problem grew considerably after the murder of her brother, Gianni, in 1997. At her worst, Versace snorted cocaine openly at fashion shows and parties.
The intervention wouldn't be the last time John stepped in to help a friend fight addiction. He told BBC Radio last month that he's been helping Eminem kick his drug habit over the past 18 months.