The images, recorded by Wildcat Haven, show the protected animal on a large branch near Huntly, Aberdeenshire.
The recording was made during a surveillance operation in the area involving camera traps.
Wildcat Haven said it was the first living wildcat to score full points on a scale which shows the level of breeding with domestic cats. Scottish Wildcat Action disputed that claim.
The rival organisation said 10 wildcats had been spotted in the area before, one of which was verified as the purest form.
Dr Paul O'Donoghue, chief scientific adviser for Wildcat Haven, said of the footage: "It feels a bit like looking at a unicorn.
"This animal is so often described as extinct, bordering on mythical, but we have always been confident they're still out there, and here's the evidence coming from quite an unexpected place."
A spokesman for Scottish Wildcat Action said: "This latest claim is certainly not news to Scottish Wildcat Action.
"The wildcat shown in this 'new' video is extremely similar to one we have already identified."
Rare footage said to be of a pure wildcat has been captured.