Real life sisters, SNSD's Jessica and f(x)'s Krystal, will perform a duet together at the SMTOWN LIVE '10 concerts.

I'm sure SM family fans know already that SMTOWN LIVE '10 concerts feature a whole lot of special stages, and this will be one of them. They've never publicly performed together, so this is exciting for both SNSD and f(x) fans alike.�SM Entertainment said of the siblings, "Jessica and Krystal have performed on the same stage in one event but never together." They both have pretty singing voices, so it'll be quite nice to hear them harmonize live. Meanwhile, a total of 80 songs by participating SME artists will be performed live in front of fans during the 6 hours concert extravaganza on August 21st in Seoul.