"It took a few months, but I was naive enough to think I'm blonde -- well I'm not naturally blonde -- but it's got to be kind of light and cute, wispy," she said. "But it really wasn't. It was revolting. It was long and coarse and black."
Growing out her armpit hair wasn't all bad, though. "It was a great party trick. If I really wanted to shock and gag people, I would show off my armpit hair at parties. It was remarkable," Faris laughed. "Chris [Pratt], my husband, was like, 'Honey, that's impressive."
Though she was excited to "go method" for the role, Faris underestimated "the power underneath my arms."
"About an hour after we wrapped the last day, I didn't have a party, but it felt like a party for me," she told host Jay Leno, 61. "I went into the shower, where I had to cut it with scissors, and then it sort of clogged the drain up."