Rihanna has defended her pop rival Britney Spears' much-criticised performance at the MTV Video Music Awards.

Spears' barely mimed rendition of her comeback single 'Gimme More' was universally derided, but according to Rihanna the performance represented Britney's best effort in the circumstances.

She says, "You can't judge her performance without knowing what was going on with her personally. She had so much pressure for that one performance.

"I'm telling you, it's not easy being on that stage. I performed for a minute and a half, and I was extremely nervous.

"To have the amount of pressure that Britney had? I don't know what I would've done. She did her best, so leave her alone."