Britney Spears has done it again -- she's No. 1 in the land.

After a tumultuous year that culminated in her being placed on a psychiatric hold, Britney Spears' remarkable comeback is now complete.

Her sixth studio album, "Circus," led by the hit single, "Womanizer," blasted to the top of the charts with 51,000 copies sold, according to figures compiled by Nielsen SoundScan.

It marks her best sales effort since "Oops!...I Did It Again," which racked up 95,000 copies in May of 2000.

Her two previous studio releases, 2003's "In the Zone" and last year's "Blackout," barely sold a combined 60,000.

Spears also grabbed the top spot south of the border, selling a whopping 505,000 copies of "Circus" in the U.S., Billboard.com reports.

Back here, Brit's big debut knocked Guns N' Roses' "Chinese Democracy" all the way down to No. 5 with sales of 22,000 -- a drop of 68 per cent from last week.

Sandwiched in between was Il Divo's "Promise" (36,000) at No. 2, Nickelback's "Dark Horse" (30,000) at No. 3, and AC/DC's "Black Ice" at No. 4.

Elvis Presley's "Christmas Duets" moved up four spots to No. 6, Taylor Swift's "Fearless" snuck up one to No. 7, and Celine Dion's "My Love: Essential Collection" occupied the No. 8 position.

Rounding out the top 10 was the compilation "MuchDance 2009" at No. 9, and Enya's "Winter Came" at No. 10.

In the U.S., Taylor Swift placed second, followed by Nickelback in third, Kanye West's "808s & Heartbreak" in fourth, and Nickelback in fifth.