My Stepmother Is an Alien

Widowed astronomer Steven Mills accidentally sends a great surge of energy out into space, threatening life on another world. They respond by dispatching one of their race disguised in deliberately attractive human form (Celeste Martin) to Earth to sort things out, accompanied by a rather less attractive superior (Bag). Steven is indeed attracted, as is his untrustworthy brother, while Celeste becomes increasingly fond of Steven's young daughter.