Seven newcomers was included to its SING-vestigators' lineup. Korean popboy bandGot7 became the first guest artist to have made crossover. Also, SING-vestigators and Kiattisak Udomnak were also played. It went surpassed to 100th episode, featuring guest artist Tattoo Colour, was aired on January 17, 2018. and Sao Sao Sao, made their reunions on this show. Both AKB48 Groups, BNK48 from Bangkok and AKB48 from Tokyo were also played. It currently holds for the longest streak in the franchise, with seventeen winning good singers.
''Season 3'' (2018—)
Saranyu Winaipanit, who he was the first guest artist, is included to the SING-vestigators' lineup. A two-part episode featuring guest artist Bodyslam was aired in the last two weeks of 2018. Crossover guest artists Lukas Graham from Denmark and Kim Dong-han from South Korea were also played. It went go on to occur three separated streaks to at least ten winning good singers. The first ever versus episode between Siriporn Yooyord and, was aired on October 30, 2019. and Clash, made their reunions to the show. It went surpassed to 200th episode, featuring guest artist Ann Mitchai, was aired on December 18, 2019.
The guest artist must attempt to guess SEE-cret songers who are "good" and "bad" without hearing them sing. SEE-cret songers must partake on every round, at which they can receive help and advice from the SING-vestigators. After eliminating one to two SEE-cret songers in each round, they would perform using real voice at the stage of truth. The last SEE-cret songer standing will do duet-perform by guest artist. The Thai version has two different formats: ;Original format Under the original format, the guest artist can simply eliminate SEE-cret songers after every round concluded; and the last SEE-cret songer will do duet-perform with. ;Versus format Under the versus format, both guest artists can eliminate one mystery singer each in the first two rounds, and then both can choose one mystery singer each to duet-perform with in the third round. The winning condition implies to each mystery singer chosen by guest artist that has been duet-performed separately, if:
One guest artist had chosen a "good singer" and another one had chosen a "bad singer"; or
Both two guest artists had chosen a "good singer" or a "bad singer".
Rounds
There were seven individuals or groups of SEE-cret songers standing on the platform with its aliases to keep their identities concealed until its initial performance. ;Singer's visual
The guest artist have time to observe and examine each SEE-cret songer based on their appearance. After this, a muted video of each SEE-cret songer that reveals only 0.3 seconds of their singing voice is played as an additional hint.
;Singer's speech
Each SEE-cret songer introduces and tells its stories with their own voice.
;Singer's lip-sync
Every SEE-cret songer performs a lip-sync of a song. Good singers lip-sync to their own voice, while bad singers lip-sync to other's voices.
;Singer's verdict
The guest artist must have then 60 seconds to make an interview to the remaining SEE-cret songers before making the final decision, at which point is depending on every SING-vestigators' opinion and/or an audience's majority voting.
;Singer's talent
The guest artist must 'predict' three remaining SEE-cret songers based on other talents, except "singing" itself. It is unrelated to the stage of truth, but it depends on their identity.
