It is interesting how this complaint comes out after the actor becomes world famous from his role in Squid Game:

“Squid Game” actor O Yeong-su has been indicted on charges of sexual misconduct, judicial officials said Friday.
The Seongnam branch of the Suwon District Prosecutors Office indicted the 78-year-old O without detention Thursday over an allegation that he inappropriately touched the body of a woman in mid-2017, the officials said.
The case dates back to December last year, when the alleged victim filed a complaint against O with police.
Police then closed the case without filing any charge against the actor in April but the prosecution later reopened the investigation at the request of the victim.
Yonhap
You can read more at the link, but from what I have read O Yeong-su claims that five years ago he held the woman’s hand to guide her around a lake.