The emerging star (and her girlish ponytail) made the scene with the release of The Notebook and Mean Girls.
"She had just dyed her hair blond and did a heavy cat eye, which she hasn't done much," her makeup artist sister Kayleen McAdams said of this '60s-inspired look.
The Wedding Crashers beauty picked up an MTV Movie Award with strawberry-tinted locks. "Being a redhead was unique," she told InStyle. "I felt very Southern."
"Rachel always comes up with fun ideas, and this lipstick was inspired by the flowers in her hair," Kayleen said of her sister's look for the Red Eye premiere. The posies, which came from a hotel room bouquet, were integrated into a bohemian braided updo by hairstylist Renato Campora.
McAdams paired lavender lids with platinum tresses.
Albert L. Ortega/WireImage
The star went bombshell to host the Academy Awards for Scientific and Technical Achievements. "We were paying homage to Marilyn Monroe with a red lip and a heavy lash strip," recalled makeup artist Troy Jensen.
"She did her own hair-a fun spur-of-the-moment thing," Kayleen said of the Married Life star's cotton candy streaks. "Only pink makeup worked."
"We wanted to do a classic look with a modern influence," Kayleen has said of this look. "To accomplish this we did a simple eye, full brow, and a punchy lip."
The Lucky Ones lead wore a sleek, modern style. "Her hair was super-short, like a boy's," said Campora. "We slicked it back for a cool, edgy look."
She debuted a new curly bob and three movies: State of Play, The Time Traveler's Wife and Sherlock Holmes.
For the world premiere of Sherlock Holmes, McAdams sported a side braid inspired by the models in Alexander Wang's Spring collection.
Tristan Gregory/Camera Press/Retna
"On Oscar night, we were going for a watercolor effect on her face: cool pastels and no harsh lines, just lots of blending," Kayleen said.
McAdams's mane man, Sebastian's Thomas Dunkin, says this cut creates volume and texture all on its own. "The long layers and mid-length bangs also make it perfect for someone who is growing out their hair," he said.
In creating a look for her sister's Midnight in Paris premiere in New York City, makeup artist Kayleen McAdams knew she'd be using a bright lip color-so she put it on first. "It brings color and life to the face so you can tailor the rest of your makeup accordingly," she explained. And in order that the finish be matte but not chalky, McAdams blotted on lip balm and topped with lip liner: "Using some matte balm helps the liner to apply more evenly."
The stunner wore long ringlets to an L.A. premiere.
For the L.A. premiere of The Vow, McAdams debuted a brand new look: Thick, eyelash-grazing bangs. "They were a fun change," hairstylist Mark Townsend told us. "We were inspired by an old Kate Moss photograph. Rachel has done wispy bangs and side bangs. We thought a full fringe could make a fresh statement."
For the Toronto premiere of Passion, McAdams wore her shoulder-length looks in loose waves.
George Pimentel/Getty Images
The actress's stands took on an auburn hue at the About Time premiere in London; she gave her lips a pink tinge.
Karwai Tang/Getty Images
McAdams went back to brown at Utah's Sundance Film Festival and parted her loose waves with a center part.
Alo Ceballos/GC Images
McAdams's blonde bob featured a deep side-part and perfectly framed her face at the Aloha premiere in L.A.
The actress styled her platinum blonde bob in soft waves at the 2016 SAG Awards.
McAdams went back to her darker roots, wearing her wavy lob in a deep side part.
Brian de Rivera Simon/Getty Images