Sandra Fluke, the Georgetown law student whom Rush Limbaugh notoriously labeled a "slut," will introduce President Barack Obama at a rally in Denver on Wednesday, offering further proof that the incumbent's campaign will use women's rights as a key issue in the 2012 presidential election.

The Obama administration set off a firestorm by requiring most employers offer free contraceptive coverage as part of their health insurance plans. The plan was opposed by Catholic bishops and other religious institutions, who lobbied against the requirement on religious freedom grounds.

Fluke rose to notoriety after testifying in Congress earlier this year in favor of the measure. The visit to Capitol Hill led Limbaugh to call her a "slut" and "prostitute," only apologizing under a hail of outrage.

Obama personally called Fluke during the peak of the uproar, expressing his concern.

"He encouraged me and supported me and thanked me for speaking out about the concerns of American women," Fluke said of the March phone call, according to the New York Daily News.

Fluke will take the stage ahead of Obama's appearance at the Auraria Campus education complex in downtown Denver. It will be one of four stops in the Centennial State, with Grand Junction, Pueblo and Colorado Springs also on his itinerary.

The 31-year-old law student's appearance follows a new Obama television ad attacking Republican opponent Mitt Romney as "out of touch" on women's issues.