On January 3, 2011, Joo released her much-awaited comeback video, titled "Bad Guy", which featured 2PM's Chansung[3] on her official YouTube channel.
On May 12, 2011, Joo released another teaser video with a new song titled "Ice Cream" featuring Super Junior's leader, Leeteuk.
The star-studded line-up included Park Jin-young, Lim Jeong-hee, Wonder Girls, Joo, 2AM, 2PM, Miss A, and San E. The two concerts took place on August 17 and 18 at the Saitama Super Arena.
On October 10, 2011, JYP Entertainment revealed that Joo had been selected as a leading actress in a musical called Youthful March, scheduled to perform from November 12, 2011, to January 29, 2012.
On October 31, 2012, JYP Entertainment announced that Joo had been selected to take on the role of Brenda in the new musical of Catch Me If You Can scheduled to have its first performance on December 14, 2012, and final on February 9, 2013.
Other prominent stars such as Girls' Generation's Sunny, CSJH The Grace's Dana and Oh Sang-eun have taken turns to take on the role previously.
[8][9] On March 5, 2014, it was announced that Joo was selected to join Beast's Yoseob in the musical remake of Full House, which ran from April 11, 2014, to June 8, 2014.
She joined the cast of Full House, which included VIXX's Leo, A Pink's Jung Eun-ji, Kim San-ho, Seo Ha-joon, and Kwak Sun-young.
She also revealed her hopes of wanting people who come to watch Full House to see her as Han Ji-eun, not as singer Joo or actress Jung Min-joo.
[20] Her younger brother, BTOB’s Jung Il-hoon, was in attendance, as were his fellow members Yook Sung-jae, Im Hyun-sik (singer), and Peniel Shin.