Both show's stories are somehow similar. In Lovesickness, FL time traveled in the ML era, but in An Ancient Love Song, ML time traveled, and they tried to change the history and tragic end of their lover. But in terms of production and story execution, the quality of An Ancient Love Song Show is higher than Lovesickness.

*In both shows Female Lead were beauties and famous but become overweight due to over eating disorder.

* In both shows FL appearance changes due to stress and eating disorder. (they are overweight)

* ML hires FL to do his chores.

* Both shows are related to entertainment industry.