Pop diva Madonna urged fans to vote for President Barack Obama in America’s November election, reports AFP, but may have caused him damage by calling him a “Black Muslim,” according to a video posted online Tuesday.

In the clip reportedly shot during a concert Monday night, she listed American icons Abraham Lincoln and Martin Luther King before turning to Obama.

“And now it is so amazing and incredible to think we have an African American in the White House,” she said in an expletive-laden speech, flanked by her troupe of black dancers at the show in Washington DC.

“So y’all better vote for **** Obama, okay?” she added, before saying: “For better or for worse, all right, we have a Black Muslim in the White House. Now that is some amazing ****. It means there is hope in this country.”

More than one in three conservative Republican voters still thinks Obama — elected the first African-American U.S. president in 2008 — is a Muslim, nearly four years after he won power, a study showed earlier this year.

Overall, 17 percent of 3,000 voters asked in June and July thought Obama was Muslim, despite the Christian church-goer’s repeated affirmations of his faith.

Obama is fighting for re-election against Republican challenger Mitt Romney and the country votes in six weeks’ time, on Nov. 6.

Representatives for the singer did not immediately respond to requests for comment on her widely-reported remarks but raised eyebrows by calling him a “Black Muslim,” according to a video posted online Tuesday.