Rock'n'roll grammar - David Bowie "Let's dance" - A2

The imperative is used to command, to order or to suggest something.

In the song "Let's dance", David Bowie probably invites someone to dance with him.

In this case "Let’s" is the short form for "let us" used to make a suggestion which includes himself.

As a reminder :

To form the imperative mode or mood with the second person singular or plural, you have to use the verb without "to" and nothing more for example “Dance”.

To form the imperative mode or mood with the first person plural, you have to use let + us + the verb without "to" for example “Let’s dance”.

The answer to the question on twitter is : US