  Very recently, Bo\v{z}in and Karapetrovi\'c solved a conjecture by proving
that the norm of the Hilbert matrix operator $\mathcal{H}$ on the Bergman space
$A^p$ is equal to $\frac{\pi}{\sin(\frac{2\pi}{p})}$ for $2 < p < 4.$ In this
article we present a partly new and simplified proof of this result. Moreover,
we calculate the exact value of the norm of $\mathcal{H}$ defined on the
Korenblum spaces $H^\infty_\alpha$ for $0 < \alpha \le 2/3$ and an upper bound
for the norm on the scale $2/3 < \alpha < 1$.
