How Barbara Walters Chose Her 'Most Fascinating' Subjects

She dishes on Scarlett Johansson, Taylor Swift, and Neil Patrick Harris.

"It really has turned out to be a sensational list," Walters told ABC News. "I'm very happy. It's a wonderful special, and the fact that we have these kinds of guests make it easy to do two hours."

Walters, who will reveal this year's Most Fascinating Person during the Dec. 14 special, made sure to curate a varied list of people, and each man or woman she interviewed surprised her in some way. Here's why each person made her list:

1. Scarlett Johansson: "What was surprising to me was that she forgot to tell me that she was married!" joked Walters, who spoke to the actress before her marriage to Romain Dauriac was made public. "But she does very few interviews, and she was extremely open." In the interview, Walters said that Johansson discusses her relationship, being a new mother, and being a sex symbol. "Her private life is very private, so we love that we could do it," she said.

2. Neil Patrick Harris: Like many people, Walters is in awe of Harris's talent and incredible work ethic. "It's such a sign of our times, the fact that Neil Patrick Harris is someone who appeals to both men and women, and is married, and has babies," she marveled. "[He and David Burtka] are today's couple... and there's nothing he can't do."

4. David Koch: Koch, the sixth richest man in the world, never does interviews -- but he did for this. Walters was fascinated by his controversial background. "People love him or hate him," she noted. "He's huge! Koch Industries owns everything from Dixie cups to oil wells, and I was happy to talk to him."

7. Oprah Winfrey: This, by Walters' count, is the fifth time she's interviewed Winfrey, with each sitdown revealing something new. "We've both grown over the years," Walters said. And still, there's one thing they always bond over: Loving their careers. "Oprah and I talk very much about taking time for ourselves," she noted, "but as she said, she can't remember the last 25 years and I feel [the same]!"