MBLAQ's Lee Joon made his fans very happy when news arrived that he'd be making a guest appearance on Invincible Youth. From the preview of the episode, it looked like he excited the G7 more than he excited his own fans.

When he first arrived on set, the cast pulled a prank on him as a welcoming event. Lee Joon was assigned to collect tree sap with T-ara's Hyomin and Secret's Sunhwa. Accidentally, he spilled the tree sap.

Then Kim Tae Woo, Brown Eyed Girls' Narsha and SNSD's Sunny decided to trick him. They brought on a cold mood by making Kim Tae Woo and Narsha fake a fight. Things got pretty heated while the two traded some harsh words at each other. Lee Joon completely fell for it and became tremendously uncomfortable in the situation.

He tried to brighten up the mood with singing, dancing and even gags. In the end, they revealed the truth to him and his heart sank a little bit.

Lee Joon seems to be the target of hidden camera all the time. Previously, his fellow group members even made him cry. Let's hope he still had a good time on the show though.

The episode airs on the 7th.