This is how I remember it: a tv station picks up a transmission from the moon and finds an alien spaceship. The aliens cloak themselves and nobody believes the story. Meanwhile the aliens are on earth preparing a standard overthrow/invasion, naturally they are hunting the people who reported the story. The aliens are desguised as humans but they need to breathe from an inhalator from time to time.
There is a benign faction inside the aliens who want to stop the invasion/manhunt and I think the alien leader’s wife is the one to rats out the alien leader to the humans. He is stressed and must use his inhalator thereby revealing him as an alien. Suddenly the cloak falls and everybody can see the spaceship on the moon.
I think it was a tv flick somewhere in the 90’s.