CoiffuresNicole Kidman Blonde, Lady Gaga Green and More Celebrity Hair ColorsNicole Kidman switched to yellow, Lady Gaga went green, and Katy Perry sported a blue 'do.08.06.09 7:00 AM ETNicole Kidman went yellow, Lady Gaga made it green, and Katy Perry sported a blue do. See the full spectrum of the stars' hair hues this summer. Kevin Winter / Getty Images; Pacific Coast NewsRedAfter experimenting with a touch of ginger back in June, Katy Perry dyed her hair a reddish pink this week that’s reminiscent of the cotton candy on her Teenage Dream album cover. Still, she has a long way to go before she’s sporting that deep Rihanna red. Sylvia Linares, WireImage / Getty Images; Joe Schildhorn / Sipa; Sang Tan / AP PhotoOrangeWas Pixie Geldof channeling her sister Peaches back in May when she dyed her blonde hair a deep peach color? Moving up the fruit spectrum, designer Vivienne Westwood has long been renowned for her shocking orange hair. But no carrot top has dominated the summer news cycle quite like former News International CEO Rebekah Brooks. Flynet; Fame; Getty ImagesYellowOne of the world’s renowned redheads, Nicole Kidman went platinum this week while shooting The Paperboy in New Orleans. (It’s unclear whether Kidman dyed it or is just sporting an amazing wig.) And based on the surprisingly strong box-office performance of The Smurfs, Kidman may have some acting competition in the always-blonde Smurfette. Marina Bay Sands via Getty Images; Alexander Tamargo / Getty ImagesGreenThough Nicki Minaj greenlit her hair first, Lady Gaga upped the ante (and the verticality) this summer by opting for a Marge Simpson–style 'do. Alas, it wasn’t blue. Niko, Le Floch / Sipa; Katy Winn / AP PhotoBlueSacré bleu! Was Katy Perry stealing Perez Hilton’s 2010 look when she attended the Jean-Charles de Castelbajac fashion show this spring, or just expressing her inner Smurfette? Kennell Krista / SipaIndigoWhen she’s not acting, Juliette Lewis fronts her own rock band, Juliette Lewis and the Licks. But here, she’s more like an indigo girl. Alberto E. Rodriguez / Getty Images; Jim Dyson / Getty ImagesVioletAt this summer’s premiere of The Hangover Part II, former American Idol Jordin Sparks flashed a purple pose. Still, it wasn’t as intense as Lily Allen’s living-doll look at the 2009 Glastonbury Festival. Admedia US / SipaRainbowWhy settle on one color of the rainbow when you can rock the whole spectrum like Avril Lavigne did in 2011 at the BRIT Awards?