Britney Spears would never be considered for a judging role on 'American Idol'.

The 'Toxic' singer and Demi Lovato are joining the panel on the US 'X Factor' with Simon Cowell and L.A. Reid, but Nigel Lythgoe - boss of 'American Idol' - claims he would not have considered the new pairing because they do not have enough experience.

He said: ''I hadn't even considered them. I always like mentors who have a lot more experience. Having said that, these two ladies have so much personal experience; it'll be interesting. I like someone who's been there and who knows the whole gamut of what these kids are going through and help them through.''

Britney - who is rumoured to have agreed a $15 million deal to be a judge on the show - revealed she is excited to be taking part in the musical talent series, and has warned Simon and L.A. to ''watch out''.

She said: ''I couldn't be more excited to join 'The X Factor' judging panel. I'm a huge fan of the show and now I get to be a part of the action. Simon and L.A. better watch out.''