Jack Black Shares How 'School of Rock' Cast Will Celebrate Film's 20th Anniversary Together (Exclusive)

Jack Black
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Jack Black told ET all about the cast's plans to celebrate the milestone anniversary.

Jack Black is gearing up to celebrate a major milestone. ET's Matt Cohen recently spoke with the 53-year-old actor, who revealed his big plans to mark School of Rock's 20th anniversary this September.

Black starred in the beloved film as substitute music teacher Dewey Finn, with young actors including Miranda Cosgrove playing his students.

"All those kids -- dig this -- they were 10 years old when we made that movie and now they're all, like, 30," Black marveled. "We're gonna get together and have a 20-year anniversary. We like to jam. I'm looking forward to seeing all of the grownups from School of Rock."

Black promised ET that he'll "100 percent" post pics and videos of the reunion on social media.

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ET's conversation with Black happened at the red carpet for The Super Mario Bros. Movie, in which the actor voices Bowser. Signing on for the project, Black told ET, was a no-brainer.

"I was introduced to Bowser through my kids. My boys play Super Mario Bros.," Black said of his and wife Tanya Haden's kids, Thomas, 14, and Samuel, 16.

"As soon as I saw Bowser I knew that he was my favorite character in the Nintendo universe, so when my agent called and said, 'Hey, they want you to play Bowser in The Super Mario Bros. Movie [it was an] instant yes," he added. "Instant yes."

The Super Mario Bros. Movie will hit theaters April 5.