Bubbly singer Colbie Caillat broke through to the top of the U.S. album chart for the first time on Wednesday, while Miley Cyrus made a surprise showing at No. 3.

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.

Cyrus' Walmart exclusive EP The Time of Our Lives sold 62,000 copies despite going on sale just last Friday. Albums traditionally hit U.S. stores on a Tuesday. Her performance on NBC's Today show the day of release likely goosed sales. All told, it's the eighth top 10 album for Cyrus -- including sets by her Hannah Montana alter ego.

Christian-leaning rock band Skillet made a mighty debut at No. 2 with Awake, selling 68,000. That is the group's best sales week yet and highest chart position. Skillet's last album, 2006's Comatose, has quietly sold 462,000 to date.

Two steps below Skillet was another record high, this time from U.K. singer/songwriter Imogen Heap. Her Ellipse enters with 48,000 at No. 5, easily giving the singer her best week ever. Heap's last album, 2005's Speak For Yourself, never went higher than No. 145 nor sold more than 7,000 copies in one week. Yet, it has steadily remained a draw to consumers, as its cumulative total stands at 431,000.

Kings of Leon's Only By The Night spent its 49th week on the Billboard 200, holding at No. 4 with 52,000. Last week's champion, Reba McEntire's Keep On Loving You, fell to No. 6 with 42,000 in its second round.

George Strait's Twang dropped five slots to No. 7 with 41,000. The Black Eyed Peas' The E.N.D. fell three to No. 8 with 36,000, and Taylor Swift's Fearless slipped one to No. 9 with 34,000. All are former chart-toppers.

Rounding out the top 10 was the Now That's What I Call Country Vol. 2 compilation, which entered with 33,000.

Overall album sales totaled 5.82 million units, up 2% compared to the sum during the previous week, but down 19% compared to the same sales week of 2008. Year-to-date album sales stand at 231.1 million, down 15% compared to the same total at this point last year.