Annie and Hallie are very similar in personality. They are both mischievous and intelligent, devising many schemes to torture Nick's fiancée, Meredith Blake, during their camping trip. They also share similar interests, such as their love for poker, fencing and Oreos with peanut butter. They are both equally good at fencing and poker but Annie is slightly better at fencing than Hallie, and vice versa. They also are both allergic to strawberries.
However, Annie still has distinct differences from Hallie. She is more proper and mature than the latter. She also uses more formal and proper vocabulary compared to Hallie. Annie is also not as talkative and seems to be more quiet than Hallie. She is bilingual or multilingual, as she spoke French when she was angered at Nick's decision to marry Meredith. She is patient and a very polite, anxious person and tends to worry more than Hallie. Annie is also more serious and can be very intelligent and shrewd, as shown when she understood Meredith's true intentions for marrying Nick, which were for his money rather than him as a person. She is not shy as well as she didn't seem embarrassed about jumping into a lake naked, even after Hallie stole her clothes. Annie also has a smaller appetite compared to Hallie, as she only had a bite of toast for breakfast.
Annie is a red haired female of average height with freckles and blue eyes. She originally had long red hair that reaches her mid-back. She usually pulled half of it back either into a pony tail or braid. That is until Hallie cut it shoulder length and side swept bangs that reached below her cheek. After that, she tied half of it back into a ponytail (Hallie's trademark hairstyle), tied it into two short braids, wore a headband, or pulled it all back into either a ponytail or with a hair clip. She also had her nails painted like Hallie's. This was so they could switch places. She also got her ears pierced by Hallie because it would look strange if she, posing as Hallie, would go back without them. Like Hallie, she wears a locket with her initial ("A") on it, which she has had since she was born. She dresses in a more formal attire than Hallie. Many of her outfits also consist of skirts and were generally white. She also speaks with a British accent, but is able to emulate an American one as well.
Role in the film
In the film, Annie was one of the twin daughters of Nick Parker and Elizabeth James along with her twin sister, Hallie Parker, and was born on October 11, 1986. However shortly after, Nick and Elizabeth divorced and Annie went with Elizabeth to London while Hallie stayed behind and lived with Nick in Napa, California. Since Annie was a baby at the time, she didn't know anything about Nick or Hallie. She grew up with Elizabeth and her father, Charles James, in London where the former worked as a wedding gown designer. In summer 1998 Elizabeth sent her to summer camp at Camp Walden where Hallie was also sent to by Nick. They do not meet until fencing class when Annie challenges Hallie to a duel. They did not recognize each other at first because of the masks they wore. Hallie agrees to the duel, but loses to Annie, who accidentally pushed Hallie into a water holder. Hallie then retaliates by pulling Annie into the water when the latter tried to apologize and pull her out of it.
They then subsequently waged a war by pulling a number of tricks on each other. However, the counselors were pulled into Hallie’s last prank. As a result, they decided to send them to the Isolation Cabin for the rest of the summer in order to work out their differences — as well as separating them from the other campers.
While in the cabin, they learn that they have many things in common and soon find out they are twins when they learn that they share the same birthdays, are the same age, and find that their pictures of their estranged parent whom they never met are the same one. They then decide to switch places to better understand their estranged parent, how they met, and why they divorced.
As Hallie, Annie bonds with Nick. She also learns of his girlfriend, Meredith, from his housekeeper, Chessy. They have been dating for the eight weeks she had been away at summer camp, while hinting at Meredith's true intention for wanting him. After being with Meredith for a while, Annie learns that she is only after Nick's money and tells Hallie she can't stop her and is no longer the only girl in Nick's life. Annie tries to warn her, but fails. She eventually gets through to her after faxing her an S.O.S.. Meanwhile, Chessy notices sudden changes in her personality.