SEOUL, June 14 -- BTS's Jungkook has issued an apology for wearing a controversial hat during a rehearsal for j-hope's encore concert.

According to Soompi, Jungkook attended the first night of j-hope's Hope On The Stage Final concert at Goyang Sports Complex. During the rehearsal, he was seen wearing a hat with the phrase "Make Tokyo Great Again."

The slogan, which resembles the phrase "Make America Great Again" associated with US President Donald Trump, sparked controversy due to historical tensions between Korea and Japan, including Japan's colonial rule over Korea.

In the early hours of June 14, Jungkook posted an apology on Weverse.

He said: "My heart feels heavy writing this kind of message after meeting you for the first time in...