Anton stole the spotlight and touched the hearts of his fans during RIIZE's concert in Mexico City.

Shortly after the concert, Anton went viral on Social Media X (formerly Twitter) after fans were completely captivated as Anton sang in Spanish and held up the Mexican flag. Not only that, Anton took the time to write a heartfelt letter to his fans in Spanish after the concert.

Anton wrote, "BRIIZE~~🧡 Are your voices still working? Tonight was definitely an unforgettable experience. It was our first time in Mexico City and the first time we met BRIIZE in Mexico, so, frankly, I was a little unsure what our first performance would be like. But tonight it was proved wrong. I don't know if it was because we were inside, but I think tonight was the strongest thing I heard our Briize cheer us up. I can't wait to come back to Mexico to perform, with more music and more Briize at our side. Thank you very much and keep your voices healthy!! I love you!! with kisses!! Apologies if my Spanish is bad!! 😂 Goodnight!"

Korean netizens and fans were also touched by Anton's kind gesture and commented:

"He's so sweet."

"He's so warm... He needs to be loved forever."

"He's so good at Spanish probably because he went to school in the States."

"Anton smiling is so cute."

"He's so sweet for writing the letter to his fans after the concert."

"I love that he wrote the letter to his fans and posted selfies."

"He's so good-looking."

"How is he so handsome and so sweet? He's perfect."

"I love Anton."

"His gesture is so cute."

"His fans in Mexico must've been so happy."

SEE ALSO: JYP says Red Velvet’s Wendy should open a vocal coaching academy