This seems to be a trivia question, but I can't find a button to add a movie into my watch list, in that movie page. The only button I can find is in the recommendation box:
I know that I can add a movie through my watch list page, but that's not what I'm looking for:
Best Answer
If it is the new site of IMDB then the "Add to watchlist" icon is just in front of the movie title. See the image below: