IU chose Baek Ah Yeon and Yoon Hyun Sang as her duet partners.

On the episode of SBS K Popstar aired on March 18th, the theme was "My Idol's Song".
IU and Miss A were seated among the audience, watching the live broadcast. When MC Boom told IU that she held her hands together tightly and was listening intently, she said, "I've been watching every episode since the preliminary rounds and never missed a single one. It felt amazing to watch the performances by the singers I previously only watched on TV. In particular, the singers I've been cheering on received good scores today, so I'm glad."
He then asked IU who she would want to duet with, to which IU replied, "Personally, I like Baek Ah Yeon" and "among the guys, I like Yoon Hyun Sang's voice". 
Watch the video below: 



Another cut of IU/Suzy:


Translation: squishyblob @ weheartiu
Source: Newsen and TV Daily via Nate