In a TV studio, you'll get an average of three to four minutes of an artist's best poses and expressions. If you're lucky, they may have to do another take or two. Use a long telephoto lens in order to blur the background, as most TV studio decor is not suitable as a background for photos. Skyscrapers, the program's logo, potted plants, etc. are disturbing factors.
A disadvantage of TV studios is that the lighting is often very flat—perfect for TV, but not for photos. If at all possible, search for a backlight. Another element that you have to take into account is the looks of the artist. Don't shoot during rehearsals when he or she is not yet wearing make-up and stage clothes. Most artists don't appreciate it as they are afraid those photos will be published. And you were never going to do that, so avoid raising any kind of suspicion.
