[This Day] f(x) performed 'Girlfriend' with After School

f(x) Krystal Victoria Girlfriend

Ten years ago, on the 13th of June, f(x)'s Krystal and Victoria performed Avril Lavigne's 'Girlfriend' together with the three members of After School.

It was a hot collaboration stage which was made possible by Inkigayo and we think Krystal's abs made it even hotter.  Check it out~