SISTAR's�Hyorin and singer�Seo In Guk had a surprise rendezvous in the middle of the night.

The two got together for a night trail run to film an advertisement, centered around the theme 'overcoming your own limitations,' for outdoor sports brand Nepa�ISENBERG. Both stars brought out their athletic side and received compliments from the staff for the professionalism they showed despite the brisk weather.

What stood out the most was the two stars' outdoor wear in the darkness.

Check out the commercial below!