The 35-year-old actress revealed as much Tuesday on Instagram in response to rumors about the project.
"Many of you asked about a book that my friend B.J. and I are working on. I heard somewhere it was a tell-all, but it's not!" she clarified.
"What I CAN tell you it will be super cool and funny and even better," she declared. "For now we are researching. Here is a cool pic of us working at my house."
Kaling and Novak met on the set of NBC sitcom The Office in 2005, and have collaborated on several projects since. The pair share a close friendship complicated by romance, and the actress called Novak her "great love" in an interview with Howard Stern in 2014.
"He is not my boyfriend, but he is not my best friend," she told InStyle magazine earlier this month. "I guess you could describe our relationship as 'romantically charged camaraderie with loud arguments,' but I don't think Facebook would accept this as a new status."
Kaling previously published memoir Is Everyone Hanging Out Without Me? (and Other Concerns) in 2011, and will release Why Not Me? in September. She created and currently stars on The Mindy Project, which will move from Fox to Hulu for season four.