Let $\{X_{i}\}_{i=1}^{\infty}$ be a memoryless real-valued source, with common pdf $f_{X}$ with support $S_{X}\subset \mathbb{R}$. Then $$- \frac{1}{n}\log_{2}f_{X^{n}}(X_{1},\ldots,X_{n})\stackrel{ n\to\infty}\to E\left[-\log_{2}f_{X}(X)\right]=h(X)$$in probability.