Flamboyant pop star Lady Gaga has scored her first No. 1 album in the US after a 99-cent promotion by Amazon.com sent the much-hyped release past the rare million-copy mark in its debut week.

According to sales data published on Tuesday by Billboard magazine, "Born This Way" sold 1.11 million copies during the week ended May 29.

It marks the biggest first-week sales total since rapper 50 Cent's "The Massacre" debuted to 1.14 million copies in March 2005. The last album to break the million mark was country starlet Taylor Swift's "Speak Now," which started with 1.01 million copies last November.

In all, just 17 albums have sold more than one million copies in their first week since tracking firm Nielsen SoundScan began collecting point-of-sales data in 1991. Boy band 'N Sync holds the first-week record with 2.4 million copies for its 2000 album "No Strings Attached."

Billboard estimated that Amazon downloads accounted for upward of 440,000 downloads of "Born This Way."

Heavy demand crashed Amazon's servers when the online retailer launched its one-day-only promotion last Monday. The firm gave fans another chance to get the album for 99 cents on Thursday.

Billboard said music industry observers had been expecting the album to sell between 650,000 and 700,000 copies before the Amazon promotion kicked in.

Amazon undertook the money-losing promotion to steal business from Apple’s iTunes, which dominates the market for digital music downloads.

Overall digital downloads for "Born This Way" totaled a record-breaking 662,000 copies, Billboard said. The old record of 288,000 downloads was held by Coldplay's 2008 album "Viva La Vida Or Death And All His Friends."

"Born This Way" marks Lady Gaga's second full-length album for Interscope Records, a unit of Vivendi SA's Universal Music Group. The 25-year-old New Yorker's 2008 debut "The Fame" peaked at No. 2 and has sold 4.2 million copies to date in the US.

The singer, famed for her outrageous costumes and lavish stage shows, has been ubiquitous on the promotional trail in recent weeks. Among her stops were the Cannes Film Festival in France, the US variety show "Saturday Night Live," and a London newspaper where she served as guest editor.

But is "Born This Way" any good? Critics said it lacked subtlety, but were divided on whether this was a good thing.

Rolling Stone described the album as "disarmingly great" while the Los Angeles Times said it draws from "the worst tendencies of the last decade of dance music." – Reuters