YoonA appeared as the special guest on the August 19 installment of fellow Girls' Generation member Sunny's radio program, 'FM Date,' to congratulate Sunny's 100th day as a DJ!

The two took a lot of cute pictures together and YoonA gave an update on her life, saying, "It has been such a long time since I got to roll around in my house during a break."  When asked to disclose a secret of YoonA's, Sunny said, "Her elbow skin is very stretchable," which was already discussed in a past 'Stargazing' episode. 

YoonA also revealed that TaeTiSeo were busily engaged in their reality program and said the trio will be making their comeback this year.

아아- 예쁜 우리 쑨디!!!! #FM데이트 (@상암신사옥 가든스튜디오)pic.twitter.com/wH8RvFhSuB

— MBC 라디오 (@radiombc) August 19, 2014