Britney Spears finds judging on X Factor "electrifying."

The "Hold It Against Me" hitmaker - who joined the show alongside Demi Lovato after Nicole Scherzinger and Paula Abdul were sacked after one season - admits she was terrified when she first signed up but eventually got into the rhythm of the talent search. "I was really nervous. You have all these people behind you and you know they're rooting on you. It's a really exciting, electrifying thing to do," she said, speaking on The Ellen DeGeneres Show.

Speaking about her judging style, Britney says she learns from the show's head judge Simon Cowell and always tries to be honest. "I used constructive criticism. I learned from the best. I prefer to be honest. I think that's the best way to go. I wouldn't want to be told something and then waste seven years of my life. I feel like it's the thing to do," she added.

However, Simon - who judged the UK version of the show before heading up the US adaptation - was shocked at how quick she made her decisions about wannabe pop stars. "I've never heard someone say no to contestants to quickly in my entire life."