Zac Efron, Vanessa Hudgens Fun Facts In 'High School Musical' As 'HSM4' Nears Production [VIDEOS]

It's no secret that "High School Musical" is one of Disney's biggest blockbusters. The special that starred Zac Efron, Vanessa Hudgens, Ashley Tisdale and Corbin Bleu is still a favorite among young viewers even after its debut 10 years ago.

 As "HSM4" is starting production soon, with a new cast and a new storyline, fans can't help but reminisce about the early days of "High School Musical." Below are some facts about the movie to help you look back at the good old days:

'High School Musical' Zac Efron, Vanessa Hudgens Facts

Zac Efron didn't actually sing in the first "High School Musical," as it was Drew Seeley who did his vocals. The actor starred in "Another Cinderella Story" and he also took over Zac Efron when "HSM" went on a tour, as the latter was filming another movie at that time. However, Zac Efron did his own songs for "High School Musical 2 and 3" per People.

Producers loved the chemistry between Zac Efron and Vanessa Hudgens early on. The two stars clicked during the audition as Troy and Gabriela, and their friendship blossomed into a real relationship off screen. They were together for four years.

According to The Richest, Zac Efron was paid $3 million for "High School Musical 3: Senior Year," while Vanessa Hudgens was paid $2 million.  Vanessa Hudgens' favorite scene from "HSM" was with Gabrielle and Troy at the rooftop where they did "Can I Have This Dance." Zac Efron's fave is "We're All In This Together," per Hollywood Life.

'High School Musical' Ashley Tisdale, Corbin Bleu Facts

Ashley Tisdale's role, Sharpay, was supposed to be black on "High School Musical," but the producers changed this when they found the right person to play Sharpay's brother, Ryan. Lucas Grabeel, a white kid who is also gay in real life, said that Tisdale was kind of a diva when they first met, which is why he thinks their character together really clicked, per Buzzfeed.

Corbin Bleu wasn't into sports before "HSM" and he couldn't believe he faked his way into the auditions. He learned to live and breathe basketball in preparation for the filming when he landed the part of Chad, the basketball star.

Tisdale is the only former "HSM" star to confirm she won't be in "HSM4." Bleu was in the open call auditions last May, but it's not clear if he's going to do a cameo. 

'High School Musical' Production Facts

Filming that grand scene featuring "We're All In This Together" took only one take because of the preparation that had to go with it. The cast had to be given a pep talk by director Kenny Ortega, which contributed to the perfect execution of the scene.

"High School Musical" was based off an old script from the 90s that was supposed to be "Grease 3." The idea was to do the TV movie with Britney Spears and Justin Timberlake, per Hollywood.