Mila Kunis says her "Oz the Great And Powerful" co-star James Franco works so hard you could call him a sadist, enjoying torturing the other actors.

"I've known James for 7 years I think, we've done eight films together," Kunis told MTV on Thursday. "I don't know James otherwise."

When the interviewer asked Mila what she thought of James's drive, Kunis started riffing.

"You want to call it drive?" she asked. "That's nice. I call it sadism."

Kunis says that Franco, who in addition to acting and directing also teaches classes at New York University's Tisch School for the Arts and University of Southern California's film school.

"He's one of the most driven human beings on the planet, and I think if he had to stand still, he wouldn't know what do to with himself," Kunis said. "He loves to share and experience and explore, and everything he looks at as art. From that felt on the floor he thinks is an art piece to that poster. Everything is art to him."

Franco explained his pursuits in academia in his blog for the Huffington Post in November.

"I am teaching six classes in all different kinds of disciplines, on both coasts," Franco wrote. "And I have turned all of the classes -- whether they are performance classes, directing classes, art classes, or writing classes -- into production-oriented, class-wide collaborations. I love when they make stuff because I can frame each class in such a way that the work can go out into the world. The level of work doesn't matter because it is an honest portrait of the students. The honesty is primary; the portrait quality of the work makes it feel like a kid's drawing framed by an adult's concept. It's also nice to be able to control the material studied and how it's talked about. I had so many classes, especially creative ones, where I hated what we were doing or the kinds of material my peers were interested in. In my current position I can guide the subject matter, especially in the classes where I bring in the source material to be adapted."