VIDEO: Julie Andrews Reveals Her Least Favorite SOUND OF MUSIC Song in New Clip from ABC Special

In an all-new clip exclusive to Billboard.com from tonight's 50th anniversary Sound of Music special on ABC, star Julie Andrews reveals that her least favorite song from the iconic film was "I Have Confidence," a number which was added for the movie and was not featured in the original Broadway musical. Watch the clip below courtesy of Billboard!

"The lyrics were a bit inane," explains Andrews. "Actually what I did, because I couldn't make sense of it and I have to have lyrics that make sense, I decided the best way to sing 'I Have Confidence' was to go completely nuts with panic and fear and busy work."

"THE UNTOLD STORY OF 'THE SOUND OF MUSIC,'" a Diane Sawyer Special. A Special Edition of "20/20" featuring an interview with Julie Andrews in Salzburg airs tonight, March 18 at 10 p.m., ET on ABC

ABC News Anchor Diane Sawyer takes viewers on an incredible journey to Austria with Oscar-winning actress Julie Andrews, exploring the mystery of "The Sound of Music" story that captured the world's attention and endured for so long. With unprecedented access, Sawyer goes behind-the-scenes to show viewers what happened beyond the frame in those famous movie scenes and re-trace the steps of the real von Trapps, who defied the Nazis and were forced to leave the country they loved. "The Untold Story of 'The Sound of Music'" is a one-hour primetime special edition of "20/20" airing TONIGHT, MARCH 18 at 10 p.m., ET on the ABC Television Network.

In the special, Sawyer and Andrews re-create the magic. Andrews opens up about her real life and her fictional one as Maria. ABC travels to landmarks including the meadow, fountain, gazebo, Mirabell Gardens and St. Michael's Church, among others. Andrews talks about her favorite and least favorite songs, and Sawyer combs through photographs and video from the set and of the real von Trapps, and meets some of the many tourists who trek annually to the town of Salzburg.

For the first time, Andrews ventures to a part of Austria she's never been - the house where the real Maria von Trapp lived - and goes with Sawyer to the train station the family used to make their escape. Mother Abbess of the Nonnberg Abbey emerges from those sacred walls to tell Sawyer what she really thinks about the film. And Christopher Plummer, who played Captain von Trapp, shares his insight on the movie and his special bond with Andrews.