The 38-year-old star is happy to juggle both professions but knows it can sometimes be detrimental to her career as she doesn't always have the time to commit to her music or movie work.
She explained: "I progress so much slower than anyone else in either discipline.
"When I came off tour, my vocal chords were so strong I should have been going into the studio and recording music. But I go and do a movie.
"And the same with the acting – the more you do it, the less anxious you become.
"And so, instead of making big progress, I just make little steps or even none."
Despite her concern, Vanessa insists she wouldn't have it any other way.
She added to Vogue magazine: "I wouldn't trade it for anything because I love doing both. I'm so happy to not have to choose. And nobody has complained yet."