Britney Spears' 'Hold It Against Me' Tops iTunes In 16 Countries

'This is absolutely incredible!' singer's manager tweets.

Forget any arguments that Britney Spears is some kind of underdog; with the release of her latest tune, "Hold It Against Me," earlier this week, the singer is certainly proving that she's still at the top of the pop heap.

Her manager, Adam Leber, tweeted that the singer was (as of press time) at the top of the iTunes charts in 16 countries: the U.S., Sweden, Australia, Greece, Switzerland, France, Ireland, Italy, Belgium, Canada, Denmark, Finland, New Zealand, Norway, Portugal and Spain.

"This is absolutely incredible!" Leber wrote. "Brit's fans never cease to amaze me." In addition to thanking the fans, Leber also shared that Brit is hard at work on the video for the track. "Went 2 dance rehearsals yesterday with @BritneySpears & @brianfriedman. HIAM video is going to be incredible to say the least. More to come," he tweeted Wednesday.

Also on Wednesday, Britney Spears thanked fans for all the support they've been showing the lead single from Brit's March album. "Couldn't of asked for a better 1/11/11..thanks to all my fans and all of the radio stations for playing HIAM!" she wrote. "I am truly blessed..."

On Tuesday, the same day the song was up for purchase on iTunes, it launched straight to #1 on the site and quickly broke all previous radio records for the most spins in the first day of release. "Top 40 outlets across the country immediately put 'Hold It Against Me' in rotation and received instant-reaction airplay at America's most-influential stations, including Z100 and WXRK in New York and KIIS and KAMP in Los Angeles," radio-industry analyst Kevin McCabe said in a statement.

Are you feeling the new Britney single like the rest of the world seems to be? Let us know in the comments!