MBLAQ's Lee Joon joined the cast of KBS' 'The Human Condition' for a day of summer vacation.

The August 17th episode aired with Lee Joon making a surprise visit to the cast's dormitories. He wore the show's team t-shirt and spent a relaxing day at the house.

The idol shared, "There's not really a concept of vacation. If I don't have work, then it's a vacation. The vacation is shorter than you think because there are magazines and interviews. We're also going to a concert abroad in a couple days."

Comedian Jung Tae Ho chimed in, "Lee Joon put forth a promise. When he goes abroad like to Mexico, he is going to wear 'The Human Condition' t-shirt at the airport or appear in front of the fans wearing it. We decided to give him the t-shirt for free in return."

Later, Lee Joon kept his promise and even took a picture wearing the team t-shirt.

What the fun episode below:

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