No Space between theorem and proof

Question

When I end a theorem and start a proof, there is a gap between them. Like here:

I don't want this gap. Is there a proper solution so that I can just deactivate this behavior for the whole document?

Here is my MWE:

\documentclass[ngerman, fontsize=11pt, DIV=15, ,BCOR = 10mm, parskip=half-, twoside]{scrbook}
\usepackage{amsthm}
\newtheorem{theorem}{Theorem}
\begin{document}
    \begin{theorem}
        There will be space, I guarantee it.
    \end{theorem}
    \begin{proof}
        As I said.
    \end{proof}
\end{document}