Entertainment News Roundup: The Iron Throne up for grabs again in 'Game of Thrones' prequel series; Director Lars von Trier diagnosed with Parkinson's disease and more

Variety chief film critic Peter Debruge was mixed on "Bullet Train," writing that "neither the characters nor the film they inhabit are particularly deep." In Australia, tributes pour out for pop star Newton-John Australians expressed shock and sadness on Tuesday as they woke up to the news that 1970s and '80s pop icon Olivia Newton-John, star of the hit movie musical "Grease", had died at age 73 at her home in Southern California.

Following is a summary of current entertainment news briefs.

The Iron Throne up for grabs again in 'Game of Thrones' prequel series

It's been three years since HBO's juggernaut show "Game of Thrones" came to a close. Now, the history of the throne is being examined in the prequel "House of the Dragon," which charters how the House of Targaryen falls into civil war. The series debuts on HBO on Aug. 21. The show starts with King Viserys Targaryen (Paddy Considine) having to choose an heir, either his dutiful daughter, Princess Rhaenyra, or his wayward and violent brother, Prince Daemon.

Director Lars von Trier diagnosed with Parkinson's disease

Danish director Lars von Trier, 66, has been diagnosed with Parkinson's disease and will do limited promotion for his upcoming supernatural TV series "Kingdom Exodus", his production company said on Monday. Von Trier often referred to as the "enfant terrible" of contemporary cinema, was in "good spirits" and is being treated for his symptoms, Zentropa said in a statement.

Hollywood actress Anne Heche in a coma since fiery car crash- spokesperson

Hollywood actress Anne Heche remained hospitalized in critical condition, comatose and connected to a breathing machine on Monday, four days after suffering severe injuries in a fiery Los Angeles car crash, a spokesperson for the performer said. Heche, 53, has been hospitalized since shortly after the compact car she was driving sped out of control in a Westside neighborhood of Los Angeles late Friday morning, plowed into a house and burst into flames, according to police.

Box office: 'Bullet Train' arrives with so-so $30.1 million debut, 'Easter Sunday' stumbles

"Bullet Train," a John Wick-ian romp with Brad Pitt in the aisle seat, arrived in theaters with a $30.1 million opening weekend. That's enough to top the domestic box office chart, but it's only a so-so result given "Bullet Train's" $90 million price tag and Pitt's star power. The Sony Pictures release will need to maintain its momentum in the coming weeks as it tries to break even or turn a profit. "Bullet Train" is trying to prove that an action flick that isn't based on a comic book or a toy line can defy the odds and resonate with audiences. But part of the issue for the film is that critics weren't on board. "Bullet Train" landed a mediocre 41% approval rating on review-aggregation website Rotten Tomatoes, with many reviewers faulting the movie for being overly derivative of the work of Guy Ritchie and Quentin Tarantino. Variety chief film critic Peter Debruge was mixed on "Bullet Train," writing that "neither the characters nor the film they inhabit are particularly deep."

In Australia, tributes pour out for pop star Newton-John

Australians expressed shock and sadness on Tuesday as they woke up to the news that 1970s and '80s pop icon Olivia Newton-John, star of the hit movie musical "Grease", had died at age 73 at her home in Southern California. From the Prime Minister on down, tributes flowed for the four-time Grammy winner, who grew up in Australia. She was hailed for her passionate work in promoting cancer research and wellness care after battling the disease for 30 years.

Pop music and 'Grease' star Olivia Newton-John dead at age 73

Singer Olivia Newton-John, who soared to the top of the world's pop music charts in the 1970s and 1980s with such tunes as "I Honestly Love You" and "Physical" and starred in the hit movie musical "Grease," died on Monday at the age 73 at her home in Southern California. The death of the British-born, Australian-raised performer was announced on her Instagram account, saying she "passed away peacefully" at her ranch home "surrounded by family and friends."

(With inputs from agencies.)