Karlie Kloss debuted her new blonde hair on Instagram and captioned another picture, "Good bye Peru ?? Thank you for a lovely adventure. And thank you @GarrenNewYork for my lovely new blonde locks." Credit: courtesy of Karlie Kloss

It's been less than two years since Karlie Kloss made the chop copied 'round the world, and now she's made another major hair change.

The American-born supermodel debuted blonde hair via Instagram on Thursday, June 26. Posing with famed photographer Mario Testino at his gallery in Lima, Peru, Kloss, 21, captioned the pic, "Celebrating the opening of a new exhibit last night at #MATE with the king of Peru, Mr @MarioTestino PS Notice anything different with my hair?"

Her lightened locks are a refreshingly natural makeover and come courtesy of celeb hairstylist Garren, who also created the Karlie back in November 2012, for a photo shoot. "She had her hair colored in the past and it was kind of a disaster," Garren told Us Weekly. "So the person in charge asked if she'd let me do it even though I wasn't involved. I know Karlie and how important her hair is to her."

To minimize damage, he avoided a platinum color and instead relied on the tones in her natural hue. "I wanted her to believe who she was," Garren, who co-founded R+Co hair care with Howard McLaren and Thom Priano, told Us. "I told Alexis [Unno, colorist at Garren New York] that I didn't want her to lift Karlie's base color and to keep it in the tone of her hair color as if she had gone to the beach—but just push it up." 

The entire process took just two hours and, thanks to the placement of the color, can grow out naturally. "She's loving the blonde and will probably keep it for now, but if she wanted to return to her natural color, it would be an easy task since she still has her base color," Garren, who equipped Kloss with Gemstone color shampoo and conditioner for upkeep, said.

To steal the easy summery hair color of Kloss, without necessarily going blonde, stay within two to three shades of your own hue, says Rita Hazan, celebrity colorist and owner of Rita Hazan New York. "Color will also get lighter in the sun so start out darker and let it naturally do its thing so you don't have a brassy problem," she tells Us. Protect hair in the sun with frequent conditioning treatments and, if needed, Rita Hazan Ultimate Shine Color Gloss in Breaking Brass and Blonde.