On the surface, Michelle Williams' most recent film roles couldn't be more different: one, a simpering bombshell, often misunderstood; the other, a kind-hearted sorceress fighting for the freedom of her people. Yet, the Oscar-nominated actress easily found common ground between "My Week With Marilyn" subject Marilyn Monroe and "Oz the Great and Powerful" witch Glinda.

"I think they do share a kind of innocence," Williams told MTV News recently, comparing her '50s bombshell to the storybook spell-caster from the upcoming Sam Raimi release.

Yet, Williams was also quick to differentiate the sources of that common quality.

"I think that Marilyn's innocence was weighted by — was something that came about because her childhood was cut off," Williams explained. "She sort of stopped developing at a certain age because of trauma and circumstances. So her innocence was kind of stagnation. It was a place that she was stuck in, and then it was something that she learned to employ as a kind of tactic. So that's her kind of innocence.

"I think Glinda's kind of innocence is 100 percent pure," she continued. "And isn't at the cost of something else. So it comes from different places, but I do think they share that quality."

Not to mention blonde locks and a penchant for billowing white dresses. But we digress.

"Oz the Great and Powerful," starring James Franco, Mila Kunis and Rachel Weisz, hits theaters March 8.

Check out everything we've got on "Oz the Great and Powerful."