Britney's new album and song are called "Hold It Against Me".  The Bellamy's seem to feel that the song is so similar to their hit that it is musical plagiarism

I personally watched the video and don't really hear any similarity musically.  I guess it's a good thing I'm not on the jury!  Check it out for yourselves and see what you think.

"It becomes somewhat uncanny if you simply double the beat of the Bellamy Brothers’ song and match it up with Britney's version,” the Bellamy Brothers’ attorney Christopher E. Schmidt said in a statement. “Literally thousands of fans for both artists have also taken notice.”