The series will also star former It's Always Sunny in Philadelphia actor David Hornsby as a magazine writer who launches a new a column about how to become the perfect gentleman. Hornsby will also script the new show.
Dillon will play a supporting role in the series as a character called Bert, although further details about his role are currently unknown.
Hornsby will serve as executive producer on the project, as he did on It's Always Sunny in Philadelphia.
Dillon currently plays series regular Johnny 'Drama' Chase on HBO's Entourage, but is currently looking for new projects following the announcement that this summer's eighth season of Entourage will be its last.
How to Be As Gentleman is based on the successful book How To Be A Gentleman: A Contemporary Guide to Common Courtesy, published by Thomas Nelson.