The 49-year-old star is one of the world's best-selling artists but she said she respects other singers in the industry that she is competing against.
Speaking about the other female artists, she said to UK newspaper The Sun: 'They're very good at their job, believe me. I've got hard competition.
'But there are certain types of music that you're good at and certain types that you're not. I mean, would I be good at R&B? I suppose you never know, maybe me and Rihanna could get together, I could dye my hair purple.'