I Summon You, Gold! (2013)

The shows have similar plots about secret births and rich and middle class families becoming in-laws.

Both dramas has a doppelganger character which is focus on the female lead.
These dramas revolve around Chaebol Families and their indifference with one another.
The poor female lead pretends to be the other on and tries to hide her identity from the spouse family.

They both have dobbelgangers in the drama
there is one rich girl and one poor girl that look alike, the rich girl disappears and the poor girl that looks like her takes her place