The season seven instalment 'Song Beneath The Song' featured performances from the show's cast.
Williams has now told Digital Spy at the Monte Carlo Television Festival that he thought the episode was "cool" and "ambitious".
However, he added that he does not expect the experiment to be repeated in the future.
Williams said: "I think we could [have another musical]. I have no reason to believe that we will.
"[Creator] Shonda [Rhimes] is very much somebody who just moves on. I don't think she lingers... She tried it and now she'll try something else crazy next year, I'm sure!"
> Jesse Williams happy with 'Grey's' romance
Watch Jesse Williams talking about the Grey's Anatomy musical below: