They’re sitting behind me at the moment, watching it from an iTunes rental.
Whoa nelly is this cheesy, even for 1978 it’s cheesy.
Ken Berry as a 'brilliant young physicist.
Sandy Duncan as his love interest, also a scientist herself.
McLean Stevenson as a gambling obsessed colleague
Roddy McDowell as a russian spy!
The science is laughable, the script isn’t too bad in terms of structure, I suppose, and the cat might give the best performance.
I think you might be thinking of This Island Earth, which has a scene where characters are having a tense discussion behind a lead slab, interrupted by the squalling arrival of Neutron, the lab cat.
As I recall it, the voice of the cat was provided by Ronnie Schell (who had played one of Gomer’s buddies on the first couple of seasons of Gomer Pyle, USMC, then was promoted to Sgt. Carter’s corporal). But the actual actor also played a military man in the film, and what with him having such a distinctive voice, they had to dub his lines.