The holiday season doesn't officially begin until watching "A Charlie Brown Christmas" on television. This year, the Christmas special will celebrate its 50th anniversary on ABC.

"A Charlie Brown Christmas" originally aired on Dec. 9, 1965 on CBS. It's the second longest-running holiday special on television after "Rudolph the Red-Nosed Reindeer, which premiered the year before on NBC.

To celebrate the golden anniversary, ABC will air the musical event, "It's Your 50th Anniversary, Charlie Brown," before the TV movie. Kristen Bell will host the special featuring the music of Vince Guaraldi, Kristen Chenowith singing "Happiness" from Broadway's "Peanuts," and Matthew Morrison singing a new original song, "Just Like Me."

Read on to learn more about the making of "A Charlie Brown Christmas" and how it almost never happened.

1. The Coca-Cola Company (via McCann-Erickson Agency) commissioned the TV special as a way to advertise during the holiday season. Executive producer Lee Mendelson and "Peanuts" creator Charles Schulz alongside director Bill Melendez had only a few days to pitch their idea, which they developed in just a couple of hours.

"The ideas flew out of our heads in a surreal way," Mendelson told USA Today. "(Schulz) said the basis of this should be the pressure that we put on our kids at Christmastime when they're in Christmas plays."

2. Schulz and his partners wanted to put the focus back on the true meaning of Christmas (the birth of Jesus) versus the over-commercialization and secularism that had taken over the holiday. The Hans Christian Anderson fairy tale, "The Fir Tree," served as inspiration for the TV special and Schulz pitched the idea for Linus' to recite the birth of Jesus from the Gospel of Luke, according to USA Today.

3. The soundtrack by the Vince Guaraldi Trio has gone triple platinum. The songs "Christmas Time Is Here" and "Hark! The Herald Angels Sing" were recorded by a choir of children from St. Paul's Episcopal Church in San Rafael, Calif. during three sessions over two weeks. "Christmas Time Is Here" was recorded just four days before the special premiered.

Guaraldi had written the theme, "Linus and Lucy," two years earlier for a documentary Mendelson planned on making about Schulz. For the special, he also wrote the originals songs, "Skating" and "Christmas Time Is Here" (Mendelson wrote the lyrics).

4. CBS and the McCann-Erickson Agency had little faith in the TV special having any success before it premiered. Even Mendelson and Melendez believed they "had failed poor Charlie Brown." The network disapproved of actual children voicing the characters and of using jazz music in a Christmas show, but had no problem with the religious themes.

"They just didn't like the show in general," Mendelson told USA Today. "They said: 'You made a nice try. We'll put it on the air, obviously, but it just doesn't work."

"A Charlie Brown Christmas" premiered to nearly half the country with 45 percent of viewers watching TV that night tuning in (an estimated 15.49 million viewers). It also received wide critical acclaim and the special won the Emmy Award for Outstanding Children's Program in 1966.

5. It is the second longest-running holiday special to date. It's flanked by "Rudolph the Red-Nosed Reindeer" at No. 1 (original airdate: Dec. 6, 1964 on NBC) and the animated "Dr. Seuss' How the Grinch Stole Christmas" (original airdate: Dec. 18, 1966 on CBS).

"A Charlie Brown Christmas" will air on Monday at 9 p.m. on ABC, following "It's Your 50th Christmas, Charlie Brown" at 8 p.m.