Thousands of people have made a Christmas pilgrimage to view the latest piece by the elusive artist Banksy.
"Season's greetings" appeared this week on a garage's walls in Port Talbot - depicting a child in snow, which is in fact ash from a skip fire.
Volunteers protecting the piece said as many as 2,000 visitors have turned up - some in the middle of the night.
Neath Port Talbot council officials have appealed for art fans to respect the local community.
It has also brought in staff to help control traffic at the Taibach site where the piece was daubed.
Banksy confirmed it was his handiwork when he posted a video on his social media Instagram channel.
Plastic protective sheeting will be put up over the artwork on Saturday - with the Welsh screen star Michael Sheen contributing to the costs.
The actor is also helping towards the bill for security in his home town, and help cover media and legal costs.
Sheen's office said the TV and film star wanted to ensure that the financial burden of safeguarding the art did not fall on the owner of the garage, Ian Lewis.
A local businessman who wants to remain anonymous will install the protective covering for free.
Garage owner Mr Lewis said he only had three hours sleep when the news broke overnight on Wednesday that the graffiti had appeared.
"I am very pleased, I think it is a smashing bit of artwork. It is good for the town and I just want to protect it, and it is here for everybody," Mr Lewis told BBC Wales earlier in the week.
The council has also urged visitors to respect the area and those living nearby.
"We understand the excitement but we want to remind visitors this is a residential area and would ask that people coming to photograph or view the Banksy do their best not disturb those living nearby," said an official.
Previous Banksy works have attracted their fair share of controversy, as art dealers descend, vandalism - and legal battles.
It includes a long running dispute that ended up in court when one of the artist's pieces was dismantled in Kent and flown to the US.
'Art Buff' was eventually returned after a High Court ruling over the graffiti that was daubed on a wall in Folkstone.
Art critic Estelle Lovatt told BBC Wales that the latest offering at Taibach in Port Talbot was clearly valuable - though difficult to put a definitive price on.
Some of Banksy's work has sold for £1m - including the image of a girl with a balloon that was dramatically shredded as it went under the hammer at an auction.
Ms Lovatt said among the factors determining its worth were "who falls in love with it".
She also questioned if its value would fall if the garage was removed, because Banksy meant it to be seen on the streets of Port Talbot.
"Regardless of its value, is that it brings people together, it brings communities together, and that's worth more than its weight in gold," she added.
She also said it would put Port Talbot on the map: "Banksy's fans don't know who he is nor care who he is and they are going to travel far and wide in order to see his work.
"It will increase Port Talbot footfall, the coffee shops and restaurants had better stock up because as people come, make pilgrimage to see this magnificent Banksy, they are going to need to be fed and watered."