What opened the presentation for Busan's bid to host the World Expo in 2030 Tuesday was the surprise appearance of Karina of K-pop girl band aespa.

A rather serious atmosphere involving an interview with children about the crises they face, such as climate change, soon gave way to an intense K-pop beat -- "Next Level" by aespa -- which was followed by Karina's message that every voice in the world matters.

"You are the future of our planet, so you can be the judge of all these ideas. Tell us which ways will work and give us a new and different future," Karina, a stage name which Yoo Ji-min acts under, was seen speaking in the clip in an apparent reference to the “Busan Initiative" unveiled during President Yoon Suk Yeol's speech. Yoon was the only head of state making a speech for the presentation of one of the candidate cities.

That was just the beginning.

South Korean singer-songwriter and K-pop star Psy appeared first for the Korean team of four speakers to drum up support for port city Busan's bid to host the 2030 event.

Park Jae-sang, who goes by his stage name of Psy, also shared his belief that every voice in the world matters.

"We (Koreans) tell a story in a big bowl of various elements mixed in well, just like a delicious bowl of bibimbap, and all the pieces come together to create empathy for people all around the world," Psy said before the World Expo organizer Bureau International des Expositions.

Korean's unique spirit that helped bind people together, mostly through K-pop music, K-dramas and others, will work the same way for the World Expo 2030, should it take place in Busan.

"That influence comes from a country that once struggled to feed its people, but now has grown this much," he said.

"I'm so excited for the World Expo 2030 Busan, because I believe it's about the things we share: our shared future, our shared challenges and the unlimited opportunities we have before us,” Psy said.

The concept of the unity of everyone mattering was also reflected in the theme song.

Premiering during the presentation was "We Will Be One" by world-renowned soprano Sumi Jo. It is the official song of the World Expo 2030 Busan.