What is the origin of the idiom "let's hear it for someone" and when to use it?

The origin of the idiom "let's hear it for someone" can be traced to the idea of rallying or encouraging applause or support for a person or group. The expression reflects a common practice in public events and performances where an emcee, host, or speaker encourages the audience to show appreciation by clapping, cheering, or applauding for someone's achievements or contributions. It is a figurative way of inviting and uniting the crowd in expressing approval, admiration, or congratulations. It is commonly employed in various events and gatherings such as concerts, sports matches, award ceremonies, talent shows, and public speeches.