Definite integral involving Legendre Polynomial

Question

Does anyone know the answer to the following definite integral:

$\displaystyle \int_{0}^{\pi}P_{\ell}(\cos\theta)\sin^{k}\theta\, d\theta$

for $k\geq1$, where $P_{\ell}(x)$ is the $\ell$-th Legendre polynomial? What about for $k=2$?