Reports of the highly-rated teenager's presence had earlier emerged on the social media website, and these now look to have been verified by the image.
Hirst scored 40 goals for Wednesday and England at youth level last season, but has made only two substitute appearances for the Owls, for whom his father David (who appears to be accompanying his son in the picture) starred between 1986 and 1997.
The 18-year-old has recently been linked with a loan move away from Hillsborough, although several Premier League sides, including Everton, have been credited with interest in the past.
However, the purpose of Hirst's apparent visit to the New York Stadium remains unclear at this stage, with moves to either Rotherham or Manchester City perhaps equally plausible - especially after the latter club hired Wednesday's former academy manager Dean Ramsdale earlier this summer.
The Sheffield-born striker has yet to agree an extension to his current deal, which expires in June 2018, despite talks over a new one having commenced earlier this year.
George Hirst in action for England U18s
And Owls fans will certainly hope it is the former explanation - if anything.
Is Hirst off to Rotherham, or are Manchester City set to snare the Sheffield Wednesday talent?