f(x)'s Sulli has a twin?

Who knew f(x)'s Sulli had a long lost twin? This recent selca has been attracting a lot of attention and obviously you can see why. Super Junior's Kim Heechul posted this photo on his Cyworld minihompy today and titled it: Sulhee where he wrote,

"I took this photo with my f(x) dongseng after filming. I took on the role of Sulli." (?? 'f(x) ????? ??? ? ???. ? ?? ??? ???..'?? ??? ????.) He added: "11 years difference. To try to make our age difference not as obvious, I even tried to do a bboo-ing bboo-ing (type of expression), however, compared to Sulli's 'heh heh~' smile, I'm just a candle next to a typhoon. Time is like an arrow sigh..Sulli is proof." (11? ??. ???? ???? ?? ????? ??? ? ???? ??? '??~' ?? ??? ?? ???? ??? ?. ??? ????? ?..??? ??)