The Devil's Agent (1962) is often listed as one of the 24 film is in which both Christopher Lee and Peter Cushing both appear. The Curse of Frankenstein, The Horror of Dracula, Horror Express and more...
But there appears to be an open question as to if Peter Cushing is actually in this movie. According to blog posts I've read, press reports of the time had Peter Cushing having been signed to the production.
One of the factors of this being an open question is that this movie is not easy to get a hold of. Sinister Cinema did release this on DVD-R, and the movie did get an official DVD release in Germany. I'm unsure if these are still available. The movie is not on any streaming service or VOD platform in the US. It does appear to currently be on the Internet Archive, but how long it lasts there is uncertain.
Having seen it on Archive, I would posit that the drunk passed out at the table in the bar with a woman who gives him looks before leaving, could very possibly be Peter Cushing.
The hair line of the drunk very much looks like the hair line of Peter Cushing.
Why Peter Cushing isn't in the movie more is a mystery that we may never know the answer to. Apparently when asked about the movie many years later, the super busy actor had no memory of the production. There is likely no one still alive who could possibly know the answer.
