The family-owned jewellers announced it has upgraded the classic Fairisle jumper design to be adorned in hundreds of hand-picked, loose diamonds.
The jumper is set to go on sale for £2m.
The unique piece was hand-crafted in a London studio by a team of diamond specialists, and features round brilliant cut diamonds alongside a scattering of rubies and emeralds.
Managing director of Purely Diamonds, Emelie Tyler said: “Nothing says Christmas like some sparkle, after all the treetops are said to ‘glisten’ during the festive period.
“For that reason, we wanted to design something unique and special to make it a Christmas like no other.”
He added: “As there are typically no jewellery trends linked to this time of year, we thought the only way to add some of the world’s most precious gems would be the most festive of all fashion…The Christmas jumper.”