Hours after a Las Vegas gunman opened fire during the city's three-day Route 91 Harvest Festival on Sunday, headlined by Jason Aldean, celebrities instantly took to social media to express their grief and condolences in the wake of the deadly tragedy.

The horrific incident has already been described as the deadliest mass shooting in modern U.S. history, after leaving at least 50 dead and more than 200 people injured. "Tonight has been beyond horrific. I still don't know what to say but wanted to let everyone know that Me and my Crew are safe. My Thoughts and prayers go out to everyone involved tonight. It hurts my heart that this would happen to anyone who was just coming out to enjoy what should have been a fun night. #heartbroken #stopthehate," Jason Aldean, who arrived on stage shortly before shots began ringing, captioned an image of the strip.

In addition to performers from the country showcase, such as Chris Young, Jake Owen, and Big & Rich, stars, including John Legend, Kate Hudson, Paris Hilton, Celine Dion, Sia, and Mariah Carey also posted messages of support in the aftermath of the shooting.

Scroll below to see how celebrities responded to the harrowing events.

Celine Dion:

Jake Owen:

Paris Hilton:

Big & Rich:

Chris Young:

Kate Hudson:

John Legend:

Mariah Carey:


Paris Jackson:

Olivia Cuplo:

Josh Groban:

Ruby Rose:

Donald Trump:

Chloë Grace Moretz: