The American star and mother of two, revealed during a television interview that she finds it difficult at times to balance motherhood and her career.
She said: "I’m always going, ‘Oh god, I’m a crap mother’. I want to get home and put my kids to bed. And then sometimes I think, ‘Oh god, I just want to be an artist’."
She went on: "I guess I always feel like there is so much more to do, so much to learn, so much to know."
The singer begins her Confessions Tour on May 21 in Los Angeles. The shows will continue until the end of July, where she will finish in Europe.