f(x)'s Krystal became a guest judge during the recording of the upcoming episode of 'Project Runway Korea Allstar'.

She featured as the guest judge as well as the mission giver and told the designers, "Please make me a dress made of only feathers." The designers fell into panic at her mission as it is difficult to make a dress out of just feathers and also expensive as well.

During the filming, Krystal revealed that she was a fan of 'Project Runway Korea' and had fun interacting with the designers. But when it was time for her to start judging, it's said she put on a professional attitude to objectively judge each entry.

The episode will air later today (4th KST), but check out the preview below in the meantime, if you haven't seen it yet!