The mechanics are a famous singer and several of their impersonators sing one measure of a song behind the blinds for four rounds.

[3] A sixth season has been confirmed after two years,[4][5] starting with a "comeback special" episode that aired on July 31, 2020.

If the real singer is eliminated, they stay in the rounds until the end (albeit with null votes).

The remaining five (or six) sing half of the next song in the hidden stage (with their positions shuffled).

After voting and discussion, the next half of the song is sung, but the doors are opened, and the impersonators faces are revealed.

The singer and three (or four) surviving impersonators sing the next song in the hidden stage, but the music does not stop.

Instead, the audience votes during the interlude, and the impersonators' and singer's positions are revealed during the second half.

Nicknames are usually qualities (like "Handsome Man Nam Jin"), places of origin (like "Jinju Kim Kyung-ho"), song titles that are relevant to their backstory as a fan (like "On The Street Kim Kwang-seok"), occupations (like "Welder Im Chang-jung"), or even puns ("Who Shin Ji/누구 신지" is a pun on the phrase "Nugushinji" which translates to "Who is it") though there can be other types.

The singer and two (or three) surviving impersonators sing the final song in the hidden stage, but the music does not stop.

The last surviving impersonator wins money depending on what place they ranked and how many votes they got.

Only the panel of celebrities would be present, and live viewers could vote online when possible during the livestream.

After all singers in a group had sung, the scores would be revealed (generally one or two digits at a time), and whoever had the most votes would move to the finals.

It worked similar to a Championship Final, expect there were ten contestants (the finalists from the past three seasons, except Kwak Dong-hyun).

A special performance featuring the majority of champions from the three seasons appeared at the end.

Note: This program airs on a cable channel/pay TV which normally has a relatively smaller audience compared to free-to-air TV/public broadcasters (KBS, SBS, MBC and EBS).