And when Sam Tyler suddenly appeared in Lancashire General Hospital without actually driving up to the entrance, I thought that had in fact happened.
But then, forty minutes and several brilliant one-liners later...
Yes, that was Yoda's big TV debut. You may only have seen the back third of him, but he was right there, in the foreground, like an annoying kid on a live news item.
Me? Sneak around inside a film set? You've got the wrong man there. Guv.
Genuine 1970s filing cabintets. Probably.
The exterior of Lancashire General Hospital.
And the scene from where I was watching.
More pictures, news from the shoot, and an explanation for any confused Star Wars fans who wandered in looking for a 900-year-old Jedi Master here.