The blonde beauty - who joins forces with legendary director Woody Allen for the third time in Vicky Cristina Barcelona - has changed dramatically since she appeared in Woody's 2005 movie Match Point.

Actress Scarlett Johansson, star of director Woody Allen's new film "Vicky Cristina Barcelona", poses at the film's premiere in Los Angeles August 4, 2008.(Xinhua/Reuters Photo)
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A source said: "The producers have been saying that Scarlett isn't the same and that she has turned into the biggest prima donna.

"These are the same producers who worked with Scarlett on Match Point. Everyone back then said she was a sweetheart but now they say, 'Scarlett has let it go to her head'."

A representative for Scarlett denies the claims, adding to the New York Post newspaper: "Scarlett loves the movie and enjoyed working with everyone on it."

Scarlett recently revealed she hates leaving her movie characters behind when shooting on her movies has wrapped.

She said: "I can't help thinking about what happens to them after the film ends. I care about them. I usually assume that my character lives happily ever after.

"In my mind every character I play ends up living in the suburbs with two-point-five children. That's just the way that I see it. I'm always thinking, 'I'm sure they're okay. "