Jimmy Stewart and Donna Reed star in “It’s a Wonderful Life”

It’s an iconic movie that holds a special place in viewers' hearts, and with one of the most memorable lines in cinema, “It’s a Wonderful Life” is a true Christmas classic. Found in homes across the world at this time of year, it airs again this Christmas Eve, Thursday, Dec. 24, on NBC.

Starring the late Jimmy Stewart (“The Philadelphia Story,” 1940) as down-on-his-luck banker George Bailey, and Donna Reed ("From Here to Eternity," 1953) as his wife, Mary, the film follows Bailey through a series of hardships leading up to an attempt to end his own life. Saved by his guardian angel, Clarence (Henry Travers, “The Invisible Man,” 1933), George is shown a world in which he had never been born in the hope that he will realize his own worth.

In this alternate timeline, George sees what could have happened if he hadn't been around during pivotal moments in his life. For example, the town of Bedford Falls, where the movie takes place, is now called Pottersville, and gone is the friendly city facade, replaced instead with cocktail bars, casinos and gentlemen’s clubs. A pharmacist George once stopped from making a fatal dispensing error is charged and imprisoned for manslaughter because George wasn’t there to fix his mistake.

Ultimately, his journey through this alternate world ends at his brother Henry's graveside, the boy having died after falling through the ice because, once again, George wasn't there to save him. This death has further implications as, in George's real timeline, Henry has grown up, gone off to war and become a hero, saving countless lives that would otherwise have been lost.

A flop at the box office at the time of its initial release -- largely due to Stewart's declining popularity and the post-war mood -- the film failed to recuperate its $3.18 million budget, only making $3.3 million and ending up only the 26th-highest grossing film in 1947 (incidentally, just one spot ahead of another 1947 Christmas classic “Miracle on 34th Street”). This box office letdown did not mean it was a critical failure, however. The film was nominated for five Academy Awards, has developed a massive cult following and has become a staple of the holiday season.

It took a while for the film to rise to its current exalted status, though. After falling into relative obscurity post-release, the film didn't return to popularity until the '70s and '80s, when it began to air almost relentlessly on television during the holiday season. In 1990, it was inducted into the Library of Congress due to its cultural, historical and esthetic significance.

When asked about his favorite scene in the film by the late Johnny Carson, Stewart said it was one of the more intimate moments with his Clarence that warmed his heart most. “When Clarence told me he was an angel who hadn't won his wings yet,” he said, “I love that.”

A scene from “It’s a Wonderful Life”

Stewart went on to describe his surprise with the later success of the film, including its prominence during the holidays and its everlasting positive message.

“It’s amazing it’s become such a Christmas picture. It came from just little bits of thinking. Just remember, no man is born to be a failure. No man is poor who has friends. It shows values that are really very close to an awful lot of us, and are really very basic American values.”

Viewers and fans aren’t the only ones who have taken something from this film. Karolyn Grimes (“The Bishop’s Wife,” 1947) -- who played little Zuzu Bailey and spoke the iconic phrase, “Every time a bell rings, an angel gets its wings” -- revealed in an interview with the Telegraph that she took home a souvenir from the set and remembers how friendly Jimmy Stewart was during her first film role.

“On set in California," she said, "the fake snow was a fascination for me because I was born and raised in Hollywood and I’d never seen snow before. Everybody joined in throwing snowballs. I still have a bauble from the Christmas tree in the film that’s in my museum at home."

According to Grimes, the lack of success the film experienced at first was a product of its era. Post-war folks wanted lighter fare, and the dark preface to the film made it less appealing to viewers than the studios had anticipated. “'It’s a Wonderful Life' is a bit dark,” she said. “After all, it’s about a man who’s going to commit suicide, and after the war, people wanted to laugh. I don’t think people were ready for it at that time.”

Stewart knew all too well the feelings associated with war. He served in the armed forces during Second World War and through to the Vietnam War, retiring as a brigadier-general. Military service didn't hinder his acting chops, though, as evidenced by this classic film and how it lives on even today as a Christmas staple.

"It's a Wonderful Life" is now inextricably linked to the holidays, which are a time of cheer and merriment, but also a time to reflect on what we have and who we share it with. In the film, George offers Mary the moon in an effort to win her love. In the end, he gave us so much more -- a lasting tribute to the strength of the human spirit. Don't miss this year's broadcast of "It's a Wonderful Life," airing Christmas Eve, Thursday, Dec. 24, on NBC.