Have SNSD's Tiffany and Sunny joined the "Secret Garden" obsession? The two members performed a song off of the SBS TV drama's OST while making a radio appearance on MBC FM4U's "Today Morning, It's Lee Moonse." The girls performed 4men's "I Can't," and earned the praise of listeners for being able to perform with such perfect vocals despite it being early in the morning. Listeners commented, "That is so SNSD!," "This is why SNSD is the best," and "Their skills are on par with the main vocals." Lee Moonse later asked the girls, "While going through diets, do you guys ever compete amongst yourselves?" The members both replied, "No, it's not like that." Tiffany continued, "We ordered pizza yesterday morning and ate it all together. But when we diet, we go all out so we support each other instead." Lee jokingly added, "It's not a violation of your contract if you gain weight, is it? I really think SNSD will last for a long time." Check it out below: http://www.youtube.com/watch?v=jlNzco3A23k Source: Sports Hankooki, TV Daily via Nate