Banksy's latest piece of work in south Wales was daubed in response to an Instagram message sent to the world-renowned artist, a man has claimed.
Gary Owen, 55, said he messaged the artist in August, asking him to highlight Port Talbot's dust problem.
The image appears on two sides of a garage in Taibach and depicts a child enjoying snow falling - the other side reveals it is a fire emitting ash.
Mr Owen said he "couldn't believe it" when Banksy confirmed it was his.
Banksy used his verified Instagram account to announce: "Season's greetings", with a video of the artwork in Port Talbot - his first to appear in Wales
Although the elusive artist did not reply to the original Instagram message, Mr Owen said he sent a follow-up thank you message, albeit requesting a slightly larger piece next time.
The father-of-one, from Margam, added: "I couldn't believe it. I thought somebody else had done it and put his name on it.
"It would have to be a heck of a coincidence for him to do something in Wales for the first time on pollution when I Instagrammed him in August."
Ian Lewis, who built the garage the artwork was painted on to prevent his car being damaged, said he had not slept over fears it might be vandalised.
Neath Port Talbot council has installed a fence around the garage to help protect it.
Deputy leader Anthony Taylor said the council had spoken to Mr Lewis and had "been in contact with other local authorities who have previously had Banksy artworks within their area, to take advice".
Mr Owen, who heard about the artwork on the news on Wednesday, said: "It's brilliant. I couldn't take it in - I didn't think it was true."
Who is Banksy?
- A famous - but anonymous - British graffiti artist
- He produces pieces of work which pop up in public places
- He began spray-painting trains and walls in his home city of Bristol in the early 90s
- But in the 2000s, he expanded his work beyond Bristol and was soon leaving his mark all over the world