The 28-year-old heiress -- who is being sued for $8 million for failing to promote her 2006 comedy "Pledge This!" -- was asked by lawyers during a pre-trial hearing in Miami Thursday if she keeps a diary for business meetings.
"I just press my name and Google it and see," she told the court.
Asked by lawyers about her calls from the producers, she testified: "With my phone I never know, because I lose it all the time. I probably get a new cellphone, like, every two weeks."
When shown a copy of her cell phone bill, she replied: "I've never seen a phone bill of mine in my life."
Asked what her responsibilities as the film's executive producer, Hilton told the court, "I'm not sure what a producer does, but -- I don't know, help get cool people in the cast?"
Hilton, who also revealed that she earns $11 million a year, claims she adequately honored her deal to promote the film.
"Any chance I got, any red carpet, any press, if I was doing something for another product... I would just bring it up, 'Oh, my new sorority film, it's going to be sexy, it's going to be really hot girls,'" she testified. "Like, I really, you know, did my best."
A lawyer for Hilton added that the investors made unreasonable and last-minute demands for publicity events because the heiress' schedule is always fully booked.
Said attorney Michael Weinstein: "She's the single busiest person on the planet."