An Ontario highway sign has received the Game of Thrones treatment.

Motorists travelling on the eastbound lanes of Highway 401 in Milton, Ont., just west of Toronto, on Friday morning saw the name of the James Snow Parkway exit sign changed to the Jon Snow Parkway.

The name James on the sign was blacked out and replaced with Jon — a reference to the character Jon Snow on the popular HBO series.

Kit Harington plays Jon Snow on HBO's Game of Thrones. (HBO)

A spokeswoman for Ontario's Ministry of Transportation says the sign was vandalized sometime early in the morning.

Astrid Poei says the sign was back to normal by about 11:45 a.m. Friday and provincial police, who were notified about the incident, will continue to monitor the area.

The parkway is named after James Snow, an Ontario politician who served as a Conservative MPP for the area from 1967 to 1985.