Osbourne tottered on to Ellen's talk show only to find her dress was too short and revealing when she sat down.
The gracious comic then took her blazer off and placed it over Osbourne's knees to spare her modesty.
'I didn't test my dress before, and I was sitting down backstage and I was like 'Oh my God, that is inappropriate.
'Thank you so much Ellen, you would all have got to see I'm wearing pink knickers.'
Osbourne then turned the talk show tables on DeGeneres, asking her if her wife, Portia de Rossi, was going to do Dancing With the Stars.
'I heard that Portia De Rossi might be doing Dancing with the Stars,” Ellen said.
“I don’t know if she’s going to do it or not. She won’t tell me.”