Heartbreaking, indeed.

Stars and fans mourned rocker Tom Petty, who died Monday evening after going into cardiac arrest.

"We are devastated to announce the untimely death of of our father, husband, brother, leader and friend Tom Petty," his longtime manager Tony Dimitriades said in a statement to USA TODAY. "He died peacefully at 8:40 p.m. PT surrounded by family, his bandmates and friends."

Reaction rushed in from every corner of the globe.

In a lengthy tribute posted to Instagram, John Mayer explained Petty's impact. "Growing up a kid in suburban Connecticut in the late ‘80s, Tom Petty’s music was the only thing like it, both on the radio and on MTV," Mayer captioned an image of the artist. "He made me believe in two things: that songwriting was everything, and that California must have felt like his music sounded."

Peter Gabriel honored Petty in a post shared on his website. “Very sad to say goodbye to Tom Petty," the In Your Eyes singer wrote, "he was a kind and generous man, an excellent musician and writer and we had daughters who have grown up together since their friendship at Sarah Lawrence College.”

Rolling Stones frontman Mick Jagger sent his thoughts to Petty's family in a tweet. "So sad about Tom Petty," Jagger said, "he made some great music."

The official account of late Beatle George Harrison, with whom Petty collaborated in the late-1980s supergroup the Traveling Wilburys, recalled him as a "tender Southern gent in life (and) a music master on stage."

Fellow Rock Hall of Famer Elton John paid tribute to Petty's "timeless" work. "He was a wonderful writer, musician and singer. Irreplacable and unique."

Kiefer Sutherland called Petty a musical giant. "To me, you will live forever," he tweeted.

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Alice Cooper recalled how Petty – "an honest renegade, a rebel and a true original" – was the kind of artist who commanded "universal respect."

Mark Ronson paid tribute to a man he liked to the Beatles.

"Growing up in the 1980s in MTV America, Tom Petty might as well have been the Beatles. Tthe music seeped into everything," wrote the music producer on Instagram. "It was on the TV, the radio. it was culturally important, it was brilliant, it was critically acclaimed. It was the music you wanted to hear in your car. It was the music you'd hear at a baseball game."

Comedian David Spade, whose Saturday Night Live tenure overlapped with a couple of the singer's performances, lamented, "Tom Petty was a stud. Very few super cool dudes from the old school left. Actual talent. Rough to hear the news."

Evan Rachel Wood tweeted immediately upon the news of Petty's death. "One more night to kill the pain. You were a staple in my life and you will be missed," she wrote.

"Safe passages to the summerlands, brother," wrote Ryan Adams. "You couldn't have left more dreams here for us. Thank you."

Gene Simmons called Petty "an exceptional talent."

"Another great man gone too soon," he tweeted. "Your legacy lives on."

More:Tom Petty’s best quotes on fame, greed and the state of rock ‘n’ roll

Many were in disbelief.

"No......not Tom Petty," wrote Martina McBride.

"Man this cannot be happening," wrote Steven Van Zandt. "Not Tom Petty please. Our deepest love and condolences to his family and band. A brother and true believer.

"Is this true????????? Please say it's not!!!!" said Reba McEntire.

Kevin Smith said Petty's music has been with him since his childhood. "One night when I was 11, I played The Waiting by #TomPetty on a jukebox 100 times in a row. Loved the man's voice & his art. RIP, Legend," he wrote.

Huey Lewis called Petty "way too young" to die. "A great writer, singer, and band leader. His music will endure."

Nikki Sixx tweeted that he was "shocked" and upset. Petty was "one of the greatest songwriters of our generation. Thank you for ALL the music."

"No words. Just thanks," tweeted Cameron Crowe.

Peter Frampton referenced the onslaught of bad news after Sunday night's terror in Las Vegas.

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"I can't believe we have lost Tom Petty on this already horrible day. My love to his wife & children and the entire Heartbreaker family," he wrote.

Stephen King felt the same way. "Tom Petty gone? That’s just so wrong. What a bad day this has been, in so many ways," he said.

Sheryl Crow called the news "unbearable...Vegas and now a great music hero has passed," she said. "You brought us so much joy, @tompetty. We will miss you."

Many fans shared videos from Tom Petty & The Heartbreakers' 40th anniversary tour, which just wrapped at the Hollywood Bowl last week.