Thousands of people dressed in blue flocked to the Jamsil Olympic Stadium in Seoul on Friday to get wet and wild with the iconic K-pop singer Psy.

Psy kicked off the first day of his nationwide tour, “Summer Swag,” this year with a video clip of himself and actor Heo Sung-tae dancing to “Kokain 2021,” the wildly popular track that took over social media with its addictive melody.

The song got everyone in the stadium on their feet, jumping to the song.

Psy soon appeared on stage to perform his latest hit, “That That,” a single produced by and featuring Suga of BTS.

Water jets sprayed the audience, eliciting roars of excitement as the crowds danced to the heady beats.

Next up, he slowed it down with the ballad “What Would Have Been?" While the track was being performed, several couples were captured by the "kiss cam" on the big screen.

Psy then took a moment to speak to the crowd, saying that the biggest difference between this year’s tour from last year’s is that they are able to go mask free.

"It makes my heart beat fast listening to your cheers of joy. I made this song to sing with people that impress me,” Psy said, as he introduced his next performance of “You Move Me.”

The first section of the concert was adorned with the first guest artist of the night, rapper Jessi.

The audience went wild when Jessi appeared on stage in a flaming red outfit singing her hit “What Type of X.”

“There are so many people here today. Thank you for having me today. I hope you are enjoying the first day of Psy’s tour. I still love P Nation and Psy,” Jessi said.

Jessi was previously housed by Psy’s label P Nation until a year ago when she joined another label More Vision.

Jessi performed two more singles, “Zoom” and “Nunu Nana,” before going offstage.

Psy pulled the curtains up for the second section of his concert with “Gentleman." It was followed by "Gangnam Style," the song that made him famous around the world, and it brought the atmosphere of the stadium to fever pitch.

Then came “Father,” a slow-tempo song that is catchy and heartfelt with lyrics depicting a father’s lonely life. A big water fountain created a screen on which the track’s music video was projected.

Psy took it up another level with the track “Ganji,” in a stunning performance with a mega dance crew dancing on lifts of different levels.

Nearing the end of the second section of his show, Psy made an announcement saying there was an important contract that he needs to sign for P Nation.

To much surprise, K-pop diva Hwasa appeared on stage and signed an exclusive contract to join Psy’s label P Nation then and there.

“This is not a performance. I actually did sign my contract with P Nation right now. I got to share a special moment with you guys. Thanks for having me and enjoy the show,” said Hwasa.

The diva performed “Maria” and “Twit” as well as her group Mamamoo’s hit tracks “Decalcomanie” and “Starry Night.”

“I think this might be the first time that an artist signs with a label on stage during a concert. We will support Hwasa to the fullest to introduce good music,” added Psy.

Psy commenced the last section of his concert with “Napal Baji” to deafening cheers.

Taking a beat from the head-bopping tunes, he dazzled the audience with his piano playing skills with the ballad “Refuge.”

“It is my pride as an artist that through this tour held every year, I get to gift you with a day of happiness. Thank you for loving me. Your love and support made this stage possible,” said Psy as he wrapped up the concert with the track “Entertainer.”

But that was only the end of the official setlist, Psy stayed on for almost another two hours of encore performances.

Psy is scheduled to visit eight more cities in the country for 11 more concerts as part of his “Summer Swag” tour this year.