Britney Spears has thanked fans for their overwhelming support for her 'Hold It Against Me' single.

The singer released the first single from her forthcoming, as-yet-untitled album to the radio on Monday, a day earlier than it was scheduled. The song has since gone to number one on MP3 downloading service iTunes.

Britney tweeted: "Don't #HOLDITAGAINSTME for coming out early. I couldn't wait any longer. Hope you don't mind.

"Anybody staying up late to get #HoldItAgainstMe on iTunes? I know I'll be awake (sic)."

After well wishes from fans, saying they loved the new track, she added: "Seriously, I have the best fans ever. I love you all so much!! Everything I do is for you! xoxo Brit (sic)."

The song - which is already being referred to by the acronym 'HIAM' - was produced by Dr. Luke, who also took to twitter to express his surprised at its reception.

He wrote: "U like the new brit single 'hold it against me' ???" he wrote. "holy f**k!!!! hold it against me is a trending topic (sic)!"