Robert Plant, lead singer of Led Zeppelin, had an alter ego "Percy" that had his way with the groupies.

In mid-1969, the members of Led Zeppelin had been bandmates for nearly a year, and they were getting close enough to joke and tease one another playfully.  One night in July, they were laughing over some boring shows on British TV.  John Paul Jones laughed, "What about this bloke Percy Thrower?  You know, the guy who does the gardening show.  It's a whole program of watching plants grow!  How exciting can you get?"                                                                                                                                                                                      

"Hey, we do the same thing," Jimmy Page interjected.  "We watch Plant grow too!"                                                                                                                                                      

Jones laughed.  "What a perfect name!  'Percy'!"  From that day on, the band members hardly ever called Plant 'Robert' again.  It was nearly always 'Percy'.  Robert never complained.