The Coachella and Stagecoach music festivals have been cancelled this year amid "growing indications" that coronavirus cases are going to surge in the autumn.
Both events were meant to have taken place in California in April, and had been rescheduled for October.
But health officials have said they are "not comfortable moving forward" - especially given how Coachella is one of the world's biggest music festivals, bringing half a million fans to an open-air site east of Los Angeles.
Image: Officials in California fear that coronavirus cases may surge in the autumn
Cameron Kaiser, who signed the order cancelling the festivals for 2020, said: "I am concerned as indications grow that COVID-19 could worsen in the fall.
"Given the projected circumstances and potential, I would not be comfortable moving forward."
Mr Kaiser stressed that the decision was not taken lightly - and he acknowledged many people will be affected.
"My first priority is the health of the community," he added.
Travis Scott, Frank Ocean, Lewis Capaldi, Calvin Harris, Lana Del Rey, Fatboy Slim and Rage Against The Machine were among the acts set to take to the stage at Coachella - while Carrie Underwood and Billy Ray Cyrus were in the line-up for the Stagecoach country music festival.
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The loss of the festivals will be a major blow to the tourism and hospitality industries in the area.
It was recently reported that Anschutz Entertainment Group, the parent company of the firm that organises Coachella and Stagecoach, was planning to lay off 15% of its workforce.
Restrictions on travel and large public events in some parts of the world mean more and more music stars are cancelling gigs.
Image: Both Coachella and Stagecoach festivals had been postponed until October
The Who, Madonna, Miley Cyrus and Avril Lavigne are among the acts that have cancelled live dates due to the outbreak.
Snowbombing, the annual alpine music festival, was due to take place in the town of Mayrhofen in Austria for a week in April, but was cancelled after Austrian authorities banned all outdoor events above 500 people.
And Glastonbury - which attracts crowds of 200,000 - was forced to abandon plans to celebrate its 50th anniversary this year. Headliners including Diana Ross, Taylor Swift and Sir Paul McCartney were due to perform.