What is the origin of the idiom "class act" and when to use it?

The idiom "class act" originated in the early 20th century and is used to describe someone or something that exemplifies exceptional elegance, style, or superior behavior. The term "class" refers to a high standard of quality, sophistication, or distinction, while "act" implies a display of performance or behavior. The phrase is used to suggest that the person or entity being referred to demonstrates admirable qualities, professionalism, or exemplary conduct, often standing out from others in their field or context.