Britney Spears and Christina Aguilera
The 'Fighter' hitmaker - who is also a coach on singing contest 'The Voice' - wishes her former 'All-New Mickey Mouse Club' co-star well in her new role on the rival talent search show.

She said: "I came up with Britney. 'Mickey Mouse Club', we were very close. Our paths have always crossed and they continue to cross. I welcome her to this family of fun and entertainment and finding new talent.
"I don't know what she's going to offer specifically, but I know she's a pro and she's going to give, I think, great advice."

As well as Britney and Demi Lovato being appointed to the 'X Factor' panel, Mariah Carey was recently announced as a new judge on 'American Idol' and Christina thinks it is great to have so many women in such high-profile roles.

She said: "I welcome these very talented women. You know this business, especially in my genre of pop, [people] pit us against one another and women against women and this and that. I'm not down for that. At this point in my life, I have no patience for it. So, I'm like, come in, the more the merrier."