Channing is highly known for originating on Broadway , for playing Lorelei in the film Gentlemen Prefer Blondes and playing Dolly in the film Hello , Dolly ! . Channing is best remembered for originating , on Broadway , the musical-comedy roles of bombshell Lorelei Lee in Gentlemen Prefer Blondes , and matchmaking widow Dolly Gallagher Levi in Hello , Dolly !