The "Fashion Police" star relit her feud with Lady Gaga in an interview for the magazine.
"I loved Lady Gaga. I totally believed in everything she stood for, until I realized she's a great big hypocrite," Osbourne told Cosmo.
Gaga has co-founded two pro LGBT organizations throughout her career and has a loud voice for the community, but Osbourne thinks the popstar has alternative motives for supporting the issue.
"You're feeding on the freaks and geeks to further your career? Do you really care about the gay community? Because if you did, you'd stand up for it more than you do," Osbourne told Cosmo.
Read the full Kelly Osbourne interview when the July issue of Cosmo hits newsstands June 4.