Natalie Portman is pals with her Black Swan co-star Mila Kunis after they shared an onscreen kiss in the ballet thriller.

She explained, "She is such a great girl and a great friend, too. We had such fun working together and now I call her Sweet Lips. It is really soft to kiss a girl."

New York City ballet dancer Nina (Portman) enters into an intense battle of wills with a talented and ambitious new arrival (Kunis) who seems intent on edging her out of the spotlight in the supernatural-flavored psychological thriller from director Darren Aronofsky.


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