The 31-year-old actress will join political heavyweights Valerie Jarrett and Cecilia Munoz at the America-Nevada Women Vote 2012 Summit, said The Hollywood Reporter.
Announcing her participation, Portman said "President Obama fights for women every day, and I am proud to stand with him on behalf of women and girls across the country.
"The president has proven that he is a strong advocate for women and a defender of the issues that are important to women and their families, from affordable health care to fair pay and quality public education."