The Office star makes her debut as a producer on the upcoming romantic comedy, in which she appears alongside Topher Grace and Malin Akerman, and Fischer feared the filmmakers would miss their chance to take the project to the big screen if she didn't offer up her credit card when they hit a snag.
The money situation soon worked out and Fischer is relieved not to be out of pocket.
Appearing on U.S. breakfast show Today on Thursday (26Apr12), she explained, "(As a producer of the film), it meant that I had to put the initial financing of the film on my credit card, my personal credit card.
"Two weeks before the movie was going to start shooting, the finances weren't in the (bank) account yet... so I was afraid we wouldn't get the movie off the ground if we didn't get started. I took a risk and I said, 'Here's my credit card, let the crew fly to Detroit', and I just crossed my fingers and luckily the finances came in and I got paid back."
Fischer met her husband, screenwriter Lee Kirk, while working on the independent movie and The Giant Mechanical Man premiered at New York's Tribeca Film Festival on Monday (23Apr12) - and she admits getting her first production completed from start to finish wasn't an easy task.
The actress, who gave birth to the couple's son Weston last September (11), added, "My husband first pitched me the story four-and-a-half years ago. It took us four-and-a-half years for him to write the film, get the financing, get it off the ground, and it was easier to fall in love, get married and have a baby than make an independent film in Hollywood!"