What is the difference between *smart_ptr and *samrt_ptr.get()

As well as I understand, dereferencing - *smart_ptr , and get() + dereferencing *smart_ptr.get() doing the same thing with smart pointers, but may be there is something under the hood that I'm not aware of, cause I've seen a lot of cases there the second approach was used, so what is the point? Does it affect performance in any way?