Answer:
Sherlock Holmes first disguised himself as a drunken man and later on, as a gentleman.
Step-by-step explanation:
Arthur Conan Doyle's Sherlock Holmes series "A Scandal in Bohemia" revolves around the story of Irene Alder and the King of Bohemia. In the story, Holmes is recruited by the King to retrieve a photo of the king and Irene that Irene supposedly tried to use to blackmail the king from marrying someone else.
To get details about Irene Adler, Holmes first disguised himself as "a drunken-looking groom, [who was] ill-kempt and side-whiskered, with an inflamed face and disreputable clothes." This will allow him to mix with the servants on the street near Miss Adler's residence and get information about her habits.
Later on, Holmes again disguised himself as "an amiable and simple-minded Nonconformist clergyman" who would get knocked down in front of Miss Adler's home. This will ensure he's taken inside the house to be treated.