A moment in time where someone whom you find completely unattractive actually looks like someone you would want to procreate with. Common among celebrities who get airbrushed beyond recognition.
(shows a magazine cover with Kristen Stewart on it actually looking pretty)
Amy: "Who do you think this is?"
Eddie: "She's pretty."
Amy: "It's Kristen Stewart."
Eddie: "Oh, she's having a situational beauty moment... good for her."