Musicals aren't a staple of Hollywood filmmaking the way they once were, but when they do come out, they almost universally get noticed. One big example was 2001's Moulin Rouge, which was nominated for eight Oscars, including a Best Actress nomination for star Nicole Kidman. The movie wowed a lot of people, and it showed off that Kidman has a solid voice. However, while audiences may have been impressed with the actress's singing ability, it seems that Nicole Kidman herself is not. She wishes she could sing as well as she could act.
Speaking with the Sydney Morning Herald, Nicole Kidman says that she actually finds singing quite frustrating, She's much more comfortable with her own skills as an actress. She knows what she's capable of and knows that she at least has the ability to put forth a great performance, but it seems she doesn't feel she can do the same when she sings. According to Kidman...
I can't do with my voice what I can do when I act and that's very frustrating. With performance, there's the possibility I may not get there. But at least I know I can try to reach it. With voice, I just can't. I wish I could sing what I feel.
It's probably a little strange for many fans to read that Nicole Kidman isn't comfortable singing. The actress got some pretty solid reviews for her performance in Moulin Rouge, and you would never guess from watching the movie that she was any less comfortable in the singing portions of the film than the acting portions. And yet, it seems that she doesn't feel she puts all the emotion into her singing performance that she's capable of doing with her acting. A lot of people may have similar feelings about their singing, but most of don't actually sound as good as Nicole Kidman does.
Part of the problem appears to be one of the current context of her life. Nicole Kidman admits that she's actually less comfortable singing than she used to be, a function of the fact that she's currently married to four-time Grammy winner Keith Urban. He is, almost certainly, a tough act to follow. And the pair weren't together when Kidman made Moulin Rouge, so perhaps she wasn't thinking as intently about her performance as she would be now.
Of course, while Nicole Kidman may not feel as at home in the recording studio, she's still willing to do it. Her latest role in HBO's The Undoing does include her singing. She performs a version of the classic "Dream a Little Dream" which sounds like it's something right in her wheelhouse. Even if she doesn't feel she can sing what she feels, I would guess many fans will disagree.