What is the origin of the idiom "look a million dollars" and when to use it?

The origin is not clear, but it is believed to have emerged in the early to mid-20th century. The phrase likely originates from the idea that someone who looks wealthy and well-dressed would be valued at a high price, such as one million dollars. Alternatively, it may have been influenced by the fact that a million dollars was a significant sum of money at the time and represented the ultimate level of wealth and success. The phrase has since become a common way to describe someone who looks exceptionally good or is dressed in an impressive manner.