On June 6, SBS' television show 'Running Man' posted a preview of the next episode online.
The preview showed the next episode to be Lee Kwang Soo's last episode on 'Running Man'.
Previously in April, it was announced that Lee Kwang Soo was stepping down from 'Running Man' due to his injury.
In the preview, Lee Kwang Soo was seen choking up while reading his letter regarding his departure from 'Running Man'.
At this time, Lee Kwang Soo was wearing an orange prison uniform that had an inmate number of 3,991.
What caught the attention of fans was his inmate number, because it was related to the time that he had been on 'Running Man'.
Lee Kwang Soo has been part of 'Running Man' since the first episode on July 11, 2010.
If counting the days from July 11, 2010, until Lee Kwang Soo's last episode which is to be aired on June 13, it becomes 3,991 days.
It seemed like the production team of 'Running Man' wanted to express their gratitude to Lee Kwang Soo for his 3,991 days of hard work this way, and fans cried upon discovering it.
(Credit= 'SBS Running Man' YouTube)