“The Fighter” star Melissa Leo played a voluntary firefighter before she arrived at a dinner hosted by Marie Claire Editor-in-Chief Anne Fulenwider last week. When the actress arrived at Fig + Olive in Los Angeles for the VIP dinner, she stepped into the ladies room to freshen up. There, she found a woman trying to put out a small fire in one of the trash cans, and Leo jumped into action, racing over to help douse the flames with water. Just as calmly as she entered, spies say that Leo — who just wrapped her role as Mamie Eisenhower, opposite Robin Williams as President Dwight D. Eisenhower in director Lee Daniels’ “The Butler” — then joined the rest of the event’s guests, including Zoe Saldana, Lea Michele, Leslie Mann, Elizabeth Olsen, Jessica Pare and Olivia Munn.