Rihanna, Carrie Underwood and Miley Cyrus have joined a superstar cast of fifteen female pop singers to record 'Just Stand Up,' a charity song in support of cancer research. Beyonce, Mariah Carey, Leona Lewis, Fergie, Mary J. Blige and more will also all take part in the fundraising single in conjunction with Stand Up to Cancer, with the goal of encouraging the public to help stop cancer from being a leading cause of death.

'Just Stand Up' will be performed live on Friday, September 5 with a simultaneous broadcast on ABC, CBS and NBC. It will be available as an iTunes download on September 2.

Listen to 'Just Stand Up'!

Leona Lewis is back with her follow-up single to her smash hit, 'Bleeding Love.' In the video for 'Better in Time,' we see the pretty songstress go through multiple makeup and costume changes as she sings about healing her broken heart as the days go by.

Leona Lewis' new album, 'Spirit,' has been dominating the charts, largely due to her smash single (and all its lovable club remixes) 'Bleeding Love.' But did you know that this British 23-year-old is basically straightedge and vegan? That's right, she doesn't smoke or drink and says "no thanks" to animal products of any kind.

"When I was 18, I had a few glasses of Alcopop -- they're bubblegummy drinks with a bit of alcohol -- and it was gross," she tells Blender magazine. "I've tasted champagne, which is gross. And I tasted wine, which I don't like."

And don't expect this stunning pop star to start dressing in barely-there outfits as her star rises. Leona is a modest girl, who's keepin' it clean. "I don't wear little miniskirts and low cut tops," she says. "If you want to show your bits off, it's up to you."

Check out more from Leona Lewis' revealing interview on Blender.com.

Although Simon Cowell's protege Leona Lewis is a fellow Brit, she's making chart-topping history right here in the U.S. Her debut record, 'Spirit,' is the No. 1 album in the States, and her smash single 'Bleeding Love' is locked in the "most played" section of iPods nationwide. Leona will be making a special performance of her hit on tonight's 'American Idol,' but until then you can check out her video for that addictive song right here.