The actor and environmentalist says that shark populations “are critical to ocean health and resiliency.”

He probably won’t be tuning in to public decision-making Tuesday on the measure, but one of Hollywood’s biggest stars backs a shark-protection measure that’s making its way through the Hawaii Legislature.

Leonardo DiCaprio on Thursday tweeted his support of House Bill 553, which would establish as an offense intentionally and knowingly “capturing, entangling, or killing” a shark in state marine waters as well as impose penalties and fines.

“Shark populations are in global decline and are critical to ocean health and resiliency,” DiCaprio said. “I support #Hawaii House Bill 553 to create a Sanctuary for Hawaii’s sharks.”

He probably won’t be tuning in to public decision-making Tuesday on the measure, but one of Hollywood’s biggest stars backs a shark-protection measure that’s making its way through the Hawaii Legislature.

Leonardo DiCaprio on Thursday tweeted his support of House Bill 553, which would establish as an offense intentionally and knowingly “capturing, entangling, or killing” a shark in state marine waters as well as impose penalties and fines.

“Shark populations are in global decline and are critical to ocean health and resiliency,” DiCaprio said. “I support #Hawaii House Bill 553 to create a Sanctuary for Hawaii’s sharks.”

Yes, this really happened.

Gov. David Ige retweeted the tweet, saying, “If this bill passes the Legislature and is sent to the governor’s office, anyone can submit their comments/testimony here.” A link is provided.

DiCaprio, 46, won an Oscar in 2016 as best actor in “The Revenant.”

Who knows, maybe his backing will help. Leo has 19.5 million Twitter followers including — who knew? — Gov. Ige and U.S. Sen. Brian Schatz. His posting on Instagram had attracted more than 200,000 likes as of midday.

Read more about why some folks support HB 553 and why others oppose it.

Read about how Hawaii’s fishing fleet is changing gear to help protect sharks.

Read how a father-and-son duo in the islands is pushing for more culturally sensitive methods for academic shark research.

And insert your own comment below about what happened to Jack at the end of “Titanic.”