emeraldarrows

Both are rich MLs co-habituating with their quirky female employees. Both MLs have a phobia and traumatic past. The same actor who is the SML of NBY is a supporting character in HMG.

Both are romantic dramas with a relationship between a seemingly cold but warm inside boss and his female employee.

Both have the main couple living together after having met years before which made a deep impression on the ML. Both MLs have traumatic past/issues. Both dramas have a similar feel/tone.

Both dramas have a similar ML - wealthy, traumatic past, manipulative, and deceptive, yet deeply in love with the FL who is the one bright spot in his life and who he met years before but she doesn't remember him. Both couples live together from the beginning.

Both dramas are about identical twin sisters with different personalities who due to circumstances end up swapping identities.

Both dramas are about identical twin sisters with different personalities who due to circumstances end up swapping identities.

While one is historical and the other modern day, both have the common theme of time travel within a loop in which the main couple are trying to change past events to prevent tragedy in the present/future. In the second loop both MLs die, but are alive again when the time changes. Both couples are very devoted to each other. Both dramas have the same actor as the ML.

Both are shorter length (shorter numbers of episodes vs. mini dramas) with a modern day/future FL who enters a historical world and becomes involved with the royal ML. She must collect pieces of an object to return home.

Both are mini dramas in which a modern day FL ends up in the world of a historical novel and becomes involved with the fictional character ML.

Both are mini dramas in which a modern day FL enters the world of a historical novel. She has a "host/guide" only she can see/hear.

Both are mini dramas about a modern day FL entering a fictional historical world (novel vs. drama).
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Both dramas are about a modern day FL entering a historical novel and becoming involved with the royal ML.