The cast of 'Running Man' and guests Park Young Gyu, Rain, Alex, Kim Ki Bang and f(x)'s Krystal�found themselves as part of Korea's newest audition program, 'R-Pop Star' - a parody of their sister program, 'K-Pop Star'!

Divided into two teams, the losing team of each mini-game would have to boot one member from the team. Although the three eliminated members were distraught at first, they soon changed their tune when it was revealed that they would be serving as judges for the final mission - an audition elimination round!

Given an hour to come up with the most creative and laugh-out-loud performance they could make, the two teams were shocked at seeing their former teammates on the judges' panel, but still pulled off amazing performances - including a bewitching Rain-Krystal couple dance that sent fans into swoons!

Check out the full episode below.

SEE ALSO: ADOR executive 'Mr. A' gives a statement about the documents/diary entries that were made public