Musicians Sheryl Crow, Nikki Sixx and Nathan Followill have remembered legendary rocker Tom Petty online following his death on Monday (02Oct17).

The 66-year-old frontman of Tom Petty & the Heartbreakers was found unconscious at his home in Malibu, California on Sunday (01Oct17) and taken to the UCLA Santa Monica Hospital, where he was placed on life support.

He passed away on Monday.

Sheryl Crow was among the first to honour the late icon on social media, as people around the world continued to mourn the country music fans killed and injured during the mass shooting at Las Vegas' Route 91 Harvest Festival on Sunday night (01Oct17).

"This is unbearable. Vegas and now a great music hero has passed," she wrote. "You brought us so much joy, @tompetty. We will miss you. #RIPTomPetty".

Singer Josh Groban added, "What a horrid day for our country, music fans and music itself. RIP Tom Petty. His songs are always good medicine. Love to his family. Not equating the two. Just....what a s**tty day."

"Tom Petty. One of the greatest songwriters of our generation.Thank you for ALL the music.Prayers to your family & band members," shared Sixx, as actor Russell Crowe simply tweeted, "Mr Petty, thanks for all of it".

Singer/actress Juliette Lewis shared video footage of Tom Petty & the Heartbreakers onstage during the star's final gig at California's Hollywood Bowl in late September (17), when the band wrapped up a 40th anniversary tour.

"THANK YOU SO VERY MUCH. #TomPetty honored to have shared your very last show on this earth," she posted on Instagram, as filmmaker Cameron Crowe, whose 1982 MTV special about Tom Petty & the Heartbreakers was his first directing gig, wrote, "no words. just thanks. @tompetty".

Cyndi Lauper, Mandy Moore, Nickelback, and actresses Alyssa Milano and Mena Suvari also shared their heartache at the huge loss, while Kings of Leon rocker Nathan Followill? admitted the news had hit him hard.

"Tom Petty was one of the biggest inspirations for me as a musician. This one will hurt for a long time," he wrote. "Truly one of the sweetest people on earth. Rest In Peace brother.

"It’s going to be hard to take the stage tonight with such a heavy heart. Luckily music is what I use to get through tough times like these. Love one another."

There were also tributes from the likes of LeAnn Rimes, Christina Perri, Martina McBride, Patricia Arquette, John Cusack, Colin Hanks, and Kevin Smith.