"Breakthrough," Caillat's second album, sold 106,000 copies during the week ended August 30, according to Nielsen SoundScan. Caillat's first album, 2007's "Coco," opened at No. 5 with 51,000 and has so far sold 2 million copies in the U.S. It yielded the hit single "Bubbly," which reached the top 10 of the Hot 100.

"You always hope for the best, but you never actually think it's going to happen," Caillat told Billboard.com from England, where she's currently touring. "I never want to get my hopes up. Everyone kept saying, 'I think it's gonna be No. 1. It's gonna be No. 1. It looks like it,' and I just kept trying to ignore it 'cause I didn't want it to not happen. And now that it is happening, I can't believe it." - more on this story

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