f(x)'s Sulli "used" SHINee's Key?

Girl group f(x) was on a recent recording of SBS Kim Jung Eun's Chocolate where someone paid them a surprise visit. After the introduction by the f(x) members, SHINee's Onew, Key and Taemin popped out, surprising everyone. During the recording, SHINee's Key revealed something interesting about Sulli, saying, "Sulli used to use me a lot during my trainee days." He continued, "When I was a trainee, Sulli was a sunbae (due to the fact that she was a trainee before him). She used to order me around, making me bring a key for her." During the recording, Sulli also revealed her diary. And that's not all as SHINee and f(x) performed an awesome stage together, hyping up the crowd. Stay tuned for this broadcast on the 31st!