1. They technically filmed the movie on the wrong field.

Although the Chicago Bears were playing on Soldier Field while Brian’s Song was filming, Brian Piccolo actually played out his whole career at Wrigley Field. It would've been a little more accurate if the movie was filmed there instead.

Image: The Everett Collection

2. James Caan was the faster runner in real life.

It seems James Caan grew up playing high school football and could run circles around Billy Dee Williams, so when they had to film their racing scene, Caan had to make himself go real slow to convince viewers that Williams' was the speedier of the two.

Image: The Everett Collection

3. Billy Dee Williams was not the original actor cast as Gale Sayers.

Louis Gossett Jr. was originally cast as Gale Sayers, not Billy Dee Williams. Just before shooting started, Gossett managed to tear his Achilles’ tendon. That's when Williams stepped in and took over the role, shattering Gossett’s spirit worse than the pain of his injury. As the story goes, producer David L. Womper made a big promise to cast Gossett in the next beefy part he could place him in to cheer the actor up. That promise took six years to fulfill, but it was worth the wait when Gossett’s 1977 performance as Fiddler in Roots won him an Emmy and made him a star.

4. 'Brian's Song' was Dick Butkus’ acting debut.

When Dick Butkus agreed to take an uncredited part in Brian's Song, it led to a long acting career for the football pro. He would go on to act in more than 50 roles in film and TV. His first credited role would come three years later, portraying Dave “The Animal” in the 1974 Emergency! episode “The Hard Hours.” That part required some emotional range, with Butkus playing a pro football player who's deeply embarrassed to be hurt after his son tackles him too hard.

5. James Caan played Brian Piccolo just before he became the infamous Sonny Corleone.

James Caan almost didn't take the part in Brian's Song because he wanted to fous on major movies. In the end, it was the strength of the script that convinced him to accept the role of Brian Piccolo. It would be the last role he'd fill before he became better-known to audiences as the intimidating hot-head Sonny Corleone in The Godfather.

6. The screenplay was written by 'Starsky and Hutch' creator William Blinn.

If Brian's Song made you legit cry your eyes out, you can thank the sentimental restraint of screenwriter William Blinn, who won an Emmy for his script. He won another five years later for co-writing part II of Roots with Ernest Kinoy. Blinn went on to create the successful ‘70s series Starsky and Hutch, but it may interest you to know he came up in the business primarily through penning TV westerns. His very first script was for an episode of Rawhide in 1962. Prince fans will also note Blinn co-wrote the script for the 1984 musical Purple Rain.

7. 'Brian's Song' won more awards than any other ABC Movie of the Week

For airing Brian's Song, ABC took home four Emmys and a Peabody Award. They also received commendations from both the NAACP and the American Cancer Society. In total, the movie was nominated for eight Emmy Awards. The only other ABC Movie of the Week films to get that kind of attention was The Immortal in 1969 (1 Emmy nomination) and That Certain Summer in 1972 (7 Emmy nominations, 1 win).

Image: Associated Press

8. The 'Brian's Song' theme was written by Songwriting Hall of Famers Alan and Marilyn Bergman.

The theme to Brian’s Song was written by celebrated songwriting team Alan and Marilyn Bergman. Before we heard “The Hands of Time” in 1971, they’d already picked up an Oscar for “The Windmills of Your Mind,” written for the 1968 film The Thomas Crown Affair. In total, they’ve collected three Oscars and two Golden Globes and, as you might expect, the acclaimed duo was also inducted into the Songwriters Hall of Fame in 1980. Their most memorable song is perhaps "The Way We Were" for the Barbra Streisand film by the same name. That song won an Oscar and hit No. 1 on Billboard charts in 1974.

9. The popularity of 'Brian's Song' led to a major theatrical release.

Most made-for-TV movies remain on the small screen, but Brian's Song had bigger ideas. Due to its critical success and popularity, Columbia Pictures decided to release it in theaters. They even kicked off the theatrical run with a fancy premiere in Chicago.

10. Gale Sayers lived in the ‘Bewitched’ house, sort of.

The interior they used to shoot Gale Sayers’ house is the same set we saw as the Stevens’ home in Bewitched. Squint and wiggle your nose, and you might see it.

11. Gale Sayers is the youngest person ever inducted in the Pro Football Hall of Fame.

Inducted into the Pro Football Hall of Fame in 1977 at only 34 years old, Gale Sayers remains the youngest person to achieve that career milestone. He also holds the rookie record for most touchdowns in a season, at 22.

12. 'Brian's Song' was once a clue on 'Jeopardy!'

In 2009, Brian’s Song was the subject of a $400 clue on Jeopardy, and the contestant got it wrong! He mixed up the players, guessing “Who is Brian Piccolo?” instead of Gale Sayers when prompted with this clue: Known as "The Kansas Comet," this Chicago Bear scored 22 touchdowns as a rookie and was immortalized in Brian's Song."

See also: 11 FAMOUS ACTORS YOU FORGOT WERE IN 'ROOTS'

Roots was an eight-part series that garnered strong ratings from the get-go, but no one could have guessed how massive it would become by the last episode. Here are 11 notable actors and performers who had a part in the series. Read more.