U.S. presidential candidate John McCain has invigorated his campaign with political Viagra. Sarah Palin has "lifted" the Republican presidential hopeful and he demanded an apology from Barack Obama, saying his rival's comment about putting lipstick on a pig is a sexist slur.

The 'American Idol' winner, who wears the band on her left ring finger to show she won't have sex before marriage, has spoken out against promiscuous teenagers.

She said: "I just have one thing to say about promise rings. It's not bad to wear a promise ring, because not everybody - guy or girl - wants to be a slut."

Jordin, 18, made the passionate speech at the MTV Video Music Awards in Los Angeles last night, after the show's host Russell Brand ridiculed the Jonas Brothers for wearing purity rings.

The British comic, who claimed the young musicians should be using their celebrity status to date, later apologised for his comments, saying: "I didn't meant to take it lightly. I don't want to piss off teenage fans."

He added cheekily: "Promise rings, I'm well up for it. But a bit of sex, it never hurt anybody."

Earlier this year, Jordin was romantically linked to R'n'B singer-songwriter Steph Jones.