NEW YORK (Reuters) - While many people try to hide their gray hair, spending hours eradicating the signs of advancing age, going gray may no longer mean reaching out for the dye bottle as "granny hair" is in vogue.

Fashion designers such as Jean-Paul Gaultier, Chanel and Gareth Pugh have all styled their models with silver hair and many have since followed suit.

Spotted on celebrities such as Lady Gaga, Pink, Rihanna, Nicole Ritchie and Kelly Osborne, the gray, white or lavender trend has been embraced by women worldwide with thousands posting pictures on social media sites under "#grannyhair".

"Granny hair is basically silver hair, any tone of gray in your hair: steel gray, silvery gray, really, really white, platinum-ish with either violet or silver undertones," New York hair stylist Jan-Marie Arteca said. "That's the trend."

Many fashion blogs and magazines say the look is the "hottest" hair color trend for 2015 while website boredpanda asked women to post pictures of their "granny hair" on a page that has since been viewed over 500,000 times.

"I love the gray. Ever since I first saw it in a magazine, I was fascinated," Jackie, 27, said at the Jeff Chastain Parlor salon during an appointment to dye her dark brown hair gray.

"It's like something that comes out, like a spark."

The process can be long however, taking at least two hours to bleach the natural hair and then add the new color. For Jackie, it took seven hours - three bleaches and two color applications - to complete the look.

"Granny hair" does not come cheap - costing from $200 up to $700, depending on hair color and condition. Touch-ups are required about every four weeks.

(Reporting by Angela Moore and Reuters Television in New York; Writing by Marie-Louise Gumuchian; Editing by Louise Ireland)