Difference between D(f)(x) and diff(f(x),x)

Hello, So, I'm using the symbolic notation and I have defined both x and f(x) as symbolic functions like this

    syms x f(x)

After a couple of operations, I get (in my Command window) a formula that includes both D(f)(x) and diff(f(x),x).

    D(f)(x)+...+diff(f(x),x)

I was wondering if there is any difference between both of them or if they both represent the derivative of f in respect towards x.

Thanks a bunch