Hot Sun is Kim Hyun-joong's fourth Japanese single, which was released on June 18, 2014, under Delicious Deli Records and Universal Music Japan.

Before the official announcement, Kim Hyun-joong was busy promoting his just completed Inspiring Generation Korean series as it will be aired through the Japanese channel DATV starting in August.

On May 31, Kim attended the special fanmeeting event with 10,000 fans in Pacifico Yokohama Convention Hall.

[5] Just like the other singles and album released by him in Japan, "Hot Sun" peaked at number one on Oricon charts as well.

[7] The day after its release, Kim met with the fans through handshaking events in Nagoya and Osaka on June 19 and 20 respectively.