But it's a good thing.
"If I'm not feeling anxious and excited and nervous, then I haven't invested much in it and I shouldn't be there," Roberts says. "So, really, I just want to put myself in a position where I am really feeling like I have to ramp up and accomplish my goals."
And Roberts wasn't the only one: Director Ryan Murphy confessed facing a bout of nerves before meeting his star.
"I was really nervous before I met her because I have been a fan, too. I have seen all of her movies," he said. "Nothing surprises me about her because what you see is what you get with Julia, which is why I think people love her and why she lasts and continues to last. Because she is very sincere, very empathetic, and compassionate. What I didn't know is how funny she was."
The two were in California's Napa Valley recently to talk to the press about "Eat, Pray, Love," which opens Friday, and they recounted plenty of laughs as the "Eat, Pray, Love" crew replicated Gilbert's round-the-world journey.
Roberts' family - including 5-year-old twins Hazel and Phinnaeus and 3-year-old Henry - also came along for the ride.
"Well, the funny thing is, they had just been in India because my husband (photographer Danny Moder) had just been working there in January and this was in October," Roberts explained. "So, we had been in Jaunpur and Agra and all these places, Goa. We were all over the entire country. They loved it. So, when I said we were going back, they were so excited. We went to all the places we hadn't been before."
Nevertheless, some of the sights were familiar, perhaps most notably an elephant that plays a key role in the movie.
"Actually that elephant that I had the scene with ... is the elephant that Phinnaeus and I had ridden in January in Jaunpur. When I walked across the ashram and saw that elephant I said, 'I know that elephant,' and it was the same elephant."
Since her box-office breakthrough in 1990's "Pretty Woman," Roberts has done little small-screen work - until now. She serves as a producer of a documentary series set to debut in January on Oprah Winfrey's new cable network.
"It's called, 'Extraordinary Moms,'" said Roberts, 42. "It really is, for me, a celebration, a show to honor moms who I think do ... I mean, every mom does amazing things every day. But we found some that really, really are extraordinary and we wanted to make a show about it. Oprah made it happen for us."
One TV gig she won't be taking is a role in her "Eat, Pray, Love" director Ryan Murphy's hit TV series, "Glee."
Explained Roberts: "Billy Crudup and I were in a Woody Allen musical a couple of years ago and so he said, 'Oh, you're a great singer,' and my husband said, 'You are a great singer.' So, now I'm going to say I am a great singer, and I'm not just going on 'Glee.'"
Roberts' next big-screen project is "Larry Crowne," a dramedy that's been shooting in Southern California in recent months and is set for release next year, reunites her with Tom Hanks, whom she described as "an amazing man and friend."
As for her life in general, Roberts said she feels "really satisfied."
Her next really demanding project? "Get ready for kindergarten."