Osbourne made the comment to Cooper about working with Stern on the NBC reality competition show, andersoncooper.com reported.
But she said Stern is "kind of awkward to work with because he's very straight. He's like, twelve o'clock, doors are closed in his room, he meditates for twenty minutes, I'm like, 'Oh, shut up!'"
Osbourne said Stern is very particular about all things, USA Today reported.
"Picky about everything, really. About everything," says Osbourne. "'You're making too much noise, turn the music down, don't slam the door' -- like that."
"He won't let anyone in the dressing room, and, see, I'm nosy. I like to have a good mooch around to see what everyone's up to. Always. And nobody's allowed in. He's got two big bodyguards that are outside his room," she added.
Osbourne admitted that Stern is a great interviewer, saying, "He's probably one of the best people at dragging things out of you, and you're like, 'What? Why did you say that?' And people will go, 'He made me!'"
"He's a lot of fun," Osbourne said.