The 41-year-old has been heavily criticised, despite admitting in an interview with Oprah Winfrey that he had doped throughout his career. However, Osbourne, who is the son of former British rocker Ozzy Osbourne, believes that Armstrong deserves credit for fighting cancer and creating charity Livestrong.
Osbourne tweeted: "Honestly I don't care that Lance doped. He gave people hope and that's more important then anything. So what if he lied. #livestrong."
Armstrong was stripped of his record seven Tour de France titles when evidence of doping came to light.