Everyone knows the predator-prey relationship of the 'tiger' and 'giraffe'of 'Running Man', but just how close are the two in real life?

Kim Jong Kook and Lee Kwang Soo participated in a duet pictorial for 'Cosmo Men', where they revealed their brotherly love, or bromance, extends off-screen even when not filming together.

Even though on-screen the two are always at each other's throat, Lee Kwang Soo actually sees Kim Jong Kook as his most reliable hyung. He said, "Every time I met Kim Jong Kook for the past 3 years, I've never paid for our food. He's a hyung who always takes care of even the smallest things. I trust him so much that to me, anything he says always seems right."

His love wasn't one-sided at all. Kim Jong Kook brought out his sentimental side as he spoke about his dongseng, saying, "He's the nicest and the most genuine and honest celebrity dongseng that I have ever met. If he has a good enough reason, I'm willing to even lend him hundreds of thousands of dollars."