The Twilight: Breaking Dawn actor told reporters at San Francisco's Comic-Con last weekend that she and director Bill Condon worked hard to bring Alice's look up to date without changing it too drastically from the original choppy bob.
"We wanted to make it a little more modern," Greene explained. "We were trying to get it exactly right and tweaking it a little bit every time.
"We made Alice a little more modern. It's always been really fun to play Alice."
Greene has previously suggested that the Twilight cast has become "like a family" over the years.
The Twilight Saga: Breaking Dawn - Part 1 is to be released in UK and US cinemas on November 18.
The cast of Twilight surprised fans at Comic-Con who had waited all night with breakfast before their panel.
Watch the Twilight Saga: Breaking Dawn Comic-Con video below: