The official version of Lady Gaga's duet with Christina Aguilera, Do What U Want, has been released. The duo performed the song last month on The Voice. The song is featured on Lady Gaga's third CD, ARTPOP, but features R Kelly singing with her. Digital Spy reports that the duet on the US singing competition came after Lady Gaga publicly apologised to Christina - who is currently a coach on the reality how - about comparisons between them, which caused an online divide between fan bases in 2010. Lady Gaga revealed that she was a "big fan" of the 33-year-old and said: "All I know is that people were talking about Christina Aguilera and Lady Gaga. "I just think it's very unfair for anybody to pit another woman against another woman. Especially in the space of music when we are all just trying to be taken seriously. "From me to her, I'm so sorry for anything anyone ever said to her because of my existence."