EXO's Sehun did not forget to leave a precious memory to his fans before entering South Korea's military service.

On Sunday, EXO's maknae took to Instagram to post a video of himself dancing to his group's 2013 Christmas song "The First Snow," four days after announcing on Weverse that he would be starting his military service on Dec. 21.

The 29-year-old idol finally joined other idols and netizens in doing the "First Snow" Challenge since the track became a hit on TikTok amid the Christmas season. He did the challenge after EXO's Lay joined the trend on the same platform.

Sehun's "First Snow" entry garnered over 19.5 million views on Instagram in just 15 hours and has been picked up and reposted by different fan accounts, making him trend on X, formerly Twitter, with over 155,000 tweets.

The creator of the "First Snow" dance challenge, who has the same name as him, also commented on Sehun's post, saying, "Thank you, Sehun-nim. From Sehun."

On Bubble, an app where idols can communicate with fans, Sehun greeted EXO-Ls -- EXO fans -- a "Merry Christmas" in advance.

He also shared that he filmed his "First Snow" challenge video after watching it once because it was so cold outside.

Fans have been sharing their mixed emotions on X as Sehun's military enlistment is happening in a few days.

"Sehun greeting us a 'Merry Christmas' in advance because he won't be able to once he enlists... I can't do this," tweeted one fan, while a second fan quipped, "Sehun can't enlist because he already served."

"Sehun is forever EXO's baby. We will wait for you Sehunnie!" wrote a third supporter.

Sehun announced through the fan community platform Weverse the news of his enlistment last Wednesday.

In a handwritten letter, he said he would commence his military service on Dec. 21 and apologized for delivering the news too late to his fans.

After greeting his fans and announcing the big news, he shared that he has been spending time alone lately and looking after himself. He proceeded to thank his fans for caring for him.

"I hope everyone stays healthy until the day we meet again. I will also come back in good health. Thank you," he ended his letter, per Soompi's English translation.