"Thanks @itslyndell for my Christmas hair!!!" Wrote Fearne next to the photo, which swiftly earnt more than 10,000 likes.
The newly engaged Radio 1 DJ also showed that her hair had not only changed in colour, but was now drastically shorter, when she uploaded a picture of the pile of pink locks that had been cut off.
Mum-of-one Fearne is currently on cloud nine following her recent engagement to Jesse Wood.
"I'm over the moon," tweeted Fearne last week. "Jesse proposed and I happened to say Yes. ❤."
Fearne and Jesse, whose father is Rolling Stone Ronnie Wood, are parents to ten-month Rex Rayne.
The Celebrity Juice team leader had hinted at her desire to tie the knot in an interview with Cosmopolitan in September.
"I'd love to get married and I'm sure Jesse would too," she said. "But we don't have any plans yet – we're so hectic with a baby and two other kids [Jesse's two children Arthur, 11, and Lola, seven], and we're both working.
"I think it's important to feel like a family unit though."