Det Hem'lige teater (The Secret Theatre) is located in Kjellerupsgade 20. The theatre stages performances of different genres, like horror and comedy. Some of the plays are off-stage or even outside.

This theatre is hardly a traditional theatre. The plays are sometimes performed off-stage, which lets the audience be up close, and a part of the show. Sometimes, the theatre even uses Aalborg City as the setting for its performances, and guides the audience around on a historical tour in the downtown area.