The 'Girl Gone Wild' singer urged fans at the Verizon Centre yesterday (September 24) to vote for Obama so that Abraham Lincoln, Martin Luther King Jr and others who fought for equality "did not die for nothing".
"It is so amazing and incredible to think that we have an African American in the White House," she declared on stage. "Those fine human beings did not die for nothing.
"They fought for our freedom, not just African Americans, but for all people... who are different, unconventional or people who want to believe in what they believe... Y'all better vote for f**king Obama, OK?"
Erroneously referring to Obama as a "black Muslim", Madonna went on to describe his election in 2008 as "some amazing s**t".
It was announced last week that Katy Perry will perform at Obama's presidential campaign fundraiser '30 Days to Victory' on October 7.