"Cheese in the Trap," a webtoon-based TV series starring popular actor Park Hae-jin, is set to become the next record breaker with viewer rates climbing to levels unseen for a weekday show.

In its fourth episode earlier this month, the tvN series broke the record for a weekday cable TV drama with a viewer rate of 6 percent, beating the previous record of 5.5 percent set by a JTBC drama in 2014.

By the fifth episode last Monday, "Cheese in the Trap" drew 6.6 percent of viewers as its SBS TV rival "Healing Camp" recorded 4.2 percent in the same time slot. The following day, the show went on to record 6.5 percent for its sixth episode, while its competitor on KBS TV drew a mere 3.9 percent.

Much of the popularity of the 16-part romance thriller has been attributed to Park, 32, who plays a college student hiding a dangerous character behind his sweet smile.

Airing at 11 p.m. on Mondays and Tuesdays, "Cheese in the Trap" has a tougher job than its weekend counterparts, but analysts say the show could even break the 10 percent mark if its popularity continues.

Last week, the show was sold to China's largest video websites, Youku and Tudou, at $2 million, the highest price in the history of Korean cable drama exports, according to its PR agency Ytree Company.

Each episode was sold for $125,000, breaking the previous record of $100,000 set by cable channel OCN's "Bad Guys" in 2014.

The drama also reached No. 1 on China's Weibo Drama Popularity Chart during its fifth episode, attracting 350 million views. The next day, it had 400 million views.

The webtoon of the same name has had more than 1.1 billion hits on South Korea's No. 1 portal site, Naver, since 2010. (Yonhap)