CHRISTINA Aguilera isn't worried about Britney Spears' comeback -- because both artists are in different leagues. The Dirrty hitmaker says she has been busy in her own "creative cave" -- and insists she isn't keeping tabs on what her old rival is getting up to in the studio. She says, "I've been so sort of in my own creative cave. But no, it's a great feeling to still be in the game with somebody that you have known for so many years, even going back to the Mickey Mouse club. We had so much fun together. "At this stage in our lives, we are so different I don't think you can put us in the same ball park." Spears, 26, is due to release her sixth studio album, Circus, in December. Aguilera's forthcoming album is currently in the recording process; the release date is to be determined.
