You Who Came from the Stars (2013)

Both dramas have this supernatural background (time travel vs. ability to see smells) and an amazing villain!
I was amazed by Shin Sung Rok in "You Who Came from the Stars" and I have to say that Nam Goong Min also excels in his evil role.
Both dramas are full of romance, suspense and also have many fun aspects. You will go through all kinds of emotions while watching.

Both are about an alien who was left behind a long, long time ago on Earth. In My Classmate from Far Far Away, this alien is the female lead while in You Who Came from the Stars it's the male lead. The setting is very different, with YWCFTS being about the adult world while MYCFFFA primarily focuses on the student life aspect and has an overall more youthful vibe. Both equally amazing dramas!

A capable but unpopular showbiz manager, Kazuko, struggles to groom a younger, new male actor, Ryo, whom she had scouted, into a star. An unmotivated Ryo slowly becomes conscious of the pleasures of acting. Bonds of camaraderie grow, and before long, love gradually blossoms between them.

Both have a ML who can teleport, and is in danger of disappearing/dying but chooses to stay with the FL despite the risk.

Lee Shin is a university student majoring in modern music. He is the vocalist of the band "The Stupid" and also plays the guitar. He is known for his good looks and his strong passion for music but is in reality a cold person who is uninterested in non-music related things and has no dreams nor plans for the future. Shin initially likes a dance professor at his university, but this all changes when he meets Lee Kyu Won. Lee Kyu Won is a bright and outgoing student who was born into a prestigious family and is majoring in traditional Korean instruments, especially the gayageum. Kyu Won's grandfather, Lee Dong Gun, is one of the top 3 traditional musicians of his age, and his biggest wish is to have his granddaughter trained to become a traditional music prodigy in 10 years' time. Trying to live up to her grandfather's expectations, Kyu Won immerses herself in training and becomes a university student who knows nothing besides traditional music. As Kyu Won's friends are fans of "The Stupid", she was forced to go to the band's concert with them. There, she saw Lee Shin performing live and is immediately captivated by him.

Both are two of the cutest romantic comedies out there. Both have swoony male leads who start out as cold but warm up to be the most adorable BFs ever. Both have hilarious female leads who do physical comedy really well. Both will make you LOL and both couples have amazing chemistry though 30b17 couple is much more innocent due to their emotional ages. Funny coincidence, both female leads also acted together in Legend of the Blue Sea when Shin Hye Sun was still a second lead actress.

Both MLs are aliens with special powers who are attempting to return home, only to decided to stay on earth, at the risk of their own lives, when they fall in love with the FL. The FL is a celebrity. Similar melancholy tone and star-crossed romance feel.

The FL is a star
The ML is her neighbor
The ML is the her superman
The comedy is almost the same
The FL sometimes clumsy