On October 23, JYP revealed a new poster, "R U Ready?", hanging over their company's building with a new version of the Wonder Girls' logo. "Wonder World" was announced as the group's second full-length album and was released on November 7, 2011 along with the single "Be My Baby". The album featured more writing and production input from the group members. Promotions for "Wonder World" began with a comeback stage on "Music Bank" on November 11 and continued through January 2012.