The legendary entertainer took to Twitter to commemorate Mackie's triumph, sharing a series of posts praising her friend and celebrating his big night.
"BOB, YOU DID IT!" Cher tweeted, replying to a tweet sharing a screenshot from Mackie's acceptance speech. "MY ❤️CANT TAKE THIS," She added. "NO ON IS BETTER THAN BOB MACKIE,& IM LIVING PROOF."