Yoon Si Yoon and Kim Hi Hoon It's easy to get lost in the plot of a K-drama and imagine on-screen rivalries spilling off-screen. Such is definitely not the case for Flower Boy Next Door co-stars Yoon Si Yoon and Kim Ji Hoon. The boys recently snapped a photo on set of the hit drama, affirming their deep love for one another. Yoon Si Yoon is seen staring at Kim Ji Hoon as they both pout their lips, hamming it up for the camera. Good to know these boys have a sense of humor, and pardon us if we wouldn't mind more of these photos, please! Are you glad to know the rivalry ends when the camera stops rolling?