The Angel of the North sculpture has an addition just in time for Christmas - a Father Christmas hat.
The red and white hat was noticed atop Gateshead's famous 65ft (20m) steel structure by motorists driving along the nearby A1 on Christmas Eve.
Several people on social media posted photographs and videos clips of the statue with its festive feature.
A group of pranksters later admitted responsibility, saying they had planned for the stunt for years.
No-one in the group wished to be named, but they told the Press Association they "wanted to do something people might find uniformly enjoyable, something that might bring people together".
Many social media users greeted the new addition positively.
Casually driving down the A1, turn to the right and there’s the Angel of the North wearing a Santa hat - amazing! Us northerners are mad for it! Merry Christmas Eve... love, peace, appreciation to you all ❤️— Iain Makepeace (@IainJoseph89) December 24, 2018
are my eyes messed up or is the angel of the north wearing a santa hat— Victoria Brown (@vikirose_x) December 24, 2018
The group said the 10-person operation began early on Christmas Eve and involved ropes, and £90-worth of fabric sewn into a hat.
One said: "Ten of us, five different vans, everyone had a bit of something in the back of their vehicle.
"We all filed out like paratroopers, everybody knew what their role was.
"We have gone to significant efforts to make sure it doesn't fly off."
Gateshead Council has been approached for comment. Tyne and Wear Fire and Rescue Service and Northumbria Police both declined to comment.
The Sir Antony Gormley-designed sculpture, which weighs about 200 tonnes, celebrated its 20th anniversary in 2018.
Despite opposition ahead of its installation, it has come to be regarded a symbol of the North of England.
In 1998 it was adorned with a custom-made shirt bearing the name and number of former Newcastle United captain Alan Shearer.
It was a stunt the artist credited with creating a "cultural shift" towards the angel.
However, not all modifications to Gormley's original vision are welcomed.
Supermarket chain Morrisons apologised in May 2014 after projecting an image of a giant baguette across the sculpture's wings.