BOYNEXTDOOR are adding emotional depth to the romance narrative of the drama.

Kakao Entertainment announced on April 17 that BOYNEXTDOOR participated in the OST for the The 21st Century Grand Prince's Wife, singing the track "No Doubt."

"No Doubt" is a country pop track built on modern guitar riffs and emotional chords. The acoustic texture is layered with the group's refreshing vocals, creating a warm and engaging sound.

The highlight comes in the latter half of the song. As the arrangement builds with dynamic instrumentation, each member's distinctive tone blends together, enhancing immersion in the drama.

BOYNEXTDOOR have consistently delivered music that captures everyday emotions with honesty and freedom. Their unembellished lyrics and polished performances have earned them strong support.

A representative expressed 기대 that the group will showcase both free-spirited energy and warm sentiment through this OST.

Meanwhile, BOYNEXTDOOR are preparing for a comeback scheduled for next month.