William R. Spencer shared a look at what is likely to have been the set of Spider-Man: No Way Home to his personal Instagram page in a video that has since been deleted. Spencer appeared as Garfield's stunt double in both The Amazing Spider-Man and its sequel. While Spencer has served as a stunt performer in a number of non-superhero films, the post also featured two fellow stunt performers who are linked to the upcoming Spider-Man film, hinting that Spencer may now be, too.
Ben Jenkin appeared in Spencer's video, whose credits include stunts for various Marvel films. Its caption also mentioned Greg Townley, who was Tom Holland's stunt double in Spider-Man: Far From Home and is already confirmed to be Holland's double in its sequel. Given the inclusion of both stunt performers, it's likely that Spencer's video was taken on the set of No Way Home and deleted because of that fact. Spencer then liked an Instagram comment asking him outright if that was the case, adding further fuel to the fire.
While Spencer is more likely than not to have been on the set of Spider-Man: No Way Home, his appearance falls short of confirmation that Garfield, too, is among the film's cast. That said, given that prior rumors have hinted at Garfield's involvement as well, the totality of evidence now available is just about as close to official confirmation as a collection of rumors could be.