Write SQL query to solve given problem: Which keywords belong to the movie titles with the highest popularity?. Keep the solution inside sql tag ```sql [SQL-Query] ```
SELECT T3.keyword_name FROM movie AS T1 INNER JOIN movie_keywords AS T2 ON T1.movie_id = T2.movie_id INNER JOIN keyword AS T3 ON T2.keyword_id = T3.keyword_id ORDER BY T1.popularity DESC LIMIT 1