CHRISTINA AGUILERA has warned pop rival BRITNEY SPEARS not to expect a comeback after her baby is born - because she's "let herself go" too much to reclaim her sex symbol status. The DIRRTY singer is horrified by the deterioration in Spears' appearance since she announced she's expecting her husband KEVIN FEDERLINE's child earlier this year (05). And Aguilera hopes the TOXIC star will be content with motherhood, because she doubts she'll ever be a pop star again. She says, "She's let herself go. I can't see a comeback on the cards." http://www3.contactmusic.com/news/index3.htm --- If Christina says it's so...then it must be so.