Rachel McAdams

Rachel McAdams and her voluminous, blonde locks. Photo: Steve Mack/FilmMagic.com

An all-star cast walked the red carpet for the premiere of "Morning Glory" at the Ziegfeld Theatre in New York City last night, but it was leading lady, Rachel McAdams, who caught everyone's eye with her sexy new 'do.

Tousled, textured and teased, the 31-year-old actress' hair has never looked better -- or bigger.

McAdams' locks were styled by Sebastian Professional hairstylist Thomas Dunkin. After collaborating with her makeup artist and wardrobe stylist, Thomas created the voluminous coif with a punch of rock star glam which looked especially stunning against the star's gray hip-hugging Lanvin strapless dress.

In "Morning Glory," McAdams plays a hard-working news producer with longer, straight brunette hair. But now the Hollywood A-lister has brightened things up with a warm blonde hue that perfectly complements her bigger, bolder style.

In addition to joining other top stars like Diane Keaton, Harrison Ford and Jeff Goldblum in this romantic comedy, McAdams also joins a major pouf hair trend this fall.

Loving this chic, sexy look? We are, too!

Thomas shares his step-by-step directions on how to get it:

1. Saturate freshly washed hair with Sebastian Professional Volupt Spray for heat protection and soft volume.

2. Blow dry hair using your hands to tousle and lift random sections while twisting hair in different directions until nearly dry.

3. Place hair in very large Velcro rollers in a brickwork pattern for maximum root lift. Complete drying with a diffuser, then allow the rollers to cool and set.

4. Remove rollers and apply a sparse amount of Sebastian Professional Matte Putty through the ends of the hair. Apply another blast of heat with the hair dryer to work up the hair's texture by massaging the roots with finger tips.

5. Part the hair low so that a big section of fringe falls sensually over one eye. To exaggerate the style and build up the shape, set the style with Sebastian Professional Re-Shaper by spraying into the stream of hot air from the hair dryer.

6. Apply Matte Putty again loosening the look with your hands and defining the sections for a disheveled but modern edge.

Know who else is setting a big hair trend these days? Take a look!

And check out some of Rachel's best style moments.