Determine the matrix that represents the following rotation of $\displaystyle \mathbb{R}^{3}$: angle $\displaystyle \frac{2\pi}{3}$, axis contains the vector $\displaystyle (1,1,1)^{t}$.

I am pretty sure I have to use Euler's Theorem somehow, but I'm just drawing a blank on how to find this matrix. Any help would be appreciated.