Question

Yesterday, I saw a video of the oath of office given by Michelle Wu, the new mayor of Boston. At the end of the speech she said "let's get to work". Now, what I am wondering is what is the difference between "let's get to work" and "let's work". I often see the phrase "get to" and I also checked it many times, but so far I still can't get it's true meaning. I hope someone is willing to help me out. Thank you very much.