At 0:00 on August 31st, the first teaser video of the new song ‘Favorite Boys’ was released on Ace’s official SNS. In the released video, Ace members show sensuous choreography with dancers along with materials such as wood and silk following Korean-style patterns and murals. In particular, the appearance of the Ace members performing performances with intense sound after the atmosphere was reversed by the appearance of the Favorite Boys mural further raised expectations for the new song 'Favorite Boys'.

Ace's fourth mini-album 'HJZM: The Butterfly Phantasy' is a new song 'Favorite Boys' with a 'Korean fantasy' that combines the beauty of Korea with an Asian concept, citing a part of Zhuang Zhou's'胡蝶之夢', a classic Chinese literature. 'Contains the message that he will become the ideal type desired by the public in a world where emotions cannot be expressed freely.