SEE ALSO: 'When The Stars Gossip' finale leaves viewers perplexed and disappointed by its 'bizarre' conclusion

Lee Si Un and Hongki previously worked together for drama 'Modern Farmer', becoming close friends. In 'Modern Farmer', Lee Si Un's character was bitten by a dog right in the chest, and Hongki happened to use a photo of Lee Si Un from the scene mentioned to decorate the top of the coffee cart.

Lee Si Un said, "Hongki, who I'm always thankful for and who is always so lively. Th... thanks. I'm really really grateful but did you have to use that picture.. keke ah-oh. Thanks so much and I love you! Hongki! #ModernFarmer's Best Scene. Director #OhJinSuk who is smug seeing our friendship. Again, thank you Hongki hehe. I'll be careful about my nipples......"

Meanwhile, the post also marks Lee Si Un's first SNS post since admitting to his relationship with actress Seo Ji Seung.